How long will it take 240V, 3000W electric immersion heater to raise the temperature of 150 litres of water in a well-lagged calorimeter made of copper of mass 20kg from 15° to 70°C?​

Answers

Answer 1

Answer:

Q = mcΔT

Where:

Q is the heat energy transferred

m is the mass of the water

c is the specific heat capacity of water

ΔT is the change in temperature

First, let's calculate the heat energy required to raise the temperature of the water:

Q = mcΔT

m = 150 kg (since 1 liter of water is approximately equal to 1 kg)

c = 4186 J/kg°C (specific heat capacity of water)

ΔT = 70°C - 15°C = 55°C

Q = (150 kg) * (4186 J/kg°C) * (55°C)

Q = 346,185,000 J

Now, let's calculate the time using the power of the electric immersion heater:

P = W/t

P = 3000 W (power of the heater)

We can rearrange the formula to solve for time:

t = W/P

t = Q/P

t = (346,185,000 J) / (3000 W)

t ≈ 115,395 seconds


Related Questions

Compare and contrast compounds and mixtures (select all that are true):


Compounds are pure substances, but mixtures are not.


When two elements bond together into a compound they have new properties.


o When two substances are mixed together in a mixture, they keep their individual properties.


Compounds are physically combined.


O Mixtures are chemically combinded.

Answers

Compounds are chemically combined pure substances with new properties, while mixtures are physically combined substances that retain their individual properties.

Compare and contrast compounds and mixtures (select all that are true):

1. Compounds are pure substances, but mixtures are not.


This statement is true. Compounds are pure substances formed by the chemical combination of two or more elements in a fixed ratio, while mixtures are combinations of two or more substances that are not chemically combined and can be physically separated.

2. When two elements bond together into a compound they have new properties.
This statement is true.

When elements chemically bond to form a compound, they create a substance with unique properties different from the individual elements.

3. When two substances are mixed together in a mixture, they keep their individual properties.

This statement is true.

In a mixture, the substances retain their individual properties because they are not chemically combined.

4. Compounds are physically combined.

This statement is false.

Compounds are chemically combined, as elements form chemical bonds to create a compound with new properties.

5. Mixtures are chemically combined.


This statement is false.

Mixtures are physically combined, as the substances in a mixture are not chemically bonded and retain their individual properties.

In summary, compounds are chemically combined pure substances with new properties, while mixtures are physically combined substances that retain their individual properties.

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how friction oppse motion ​

Answers

Answer:

setting a stationary body in motion.

Explanation:

like a stationary car will start moving when driving force is applied

A 50. 0 kg ice skater is standing at rest on the ice holding a 2. 0 kg medicine ball. She throws the medicine ball to the right with a horizontal velocity of 1. 8 m/s. What is the velocity of the skater after she throws the ball?

Answers

A 50.0 kg ice skater is standing at rest on the ice holding a 2.0 kg medicine ball. She throws the medicine ball to the right with a horizontal velocity of 1. 8 m/s.

Assuming there is no external force acting on the system, we can use conservation of momentum to solve this problem.

The initial momentum of the system is zero since the skater and the medicine ball are at rest. The final momentum of the system must also be zero since there are no external forces acting on it. This means that the momentum of the medicine ball to the right must be cancelled out by the momentum of the skater to the left.

Let v be the velocity of the skater after throwing the ball. By conservation of momentum

(2.0 kg)(1.8 m/s) = (50.0 kg + 2.0 kg) v

Simplifying

v = (2.0 kg)(1.8 m/s) / (50.0 kg + 2.0 kg)

v = 0.0643 m/s

Therefore, the skater's velocity after throwing the ball is 0.0643 m/s to the right.

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Como puedo saber la carga de una partícula en un campo magnético

Answers

The charge of a particle in a magnetic field can be determined by measuring the force, velocity, and strength of the magnetic field using the Lorentz force equation. There are various methods to measure the charge, such as using a particle accelerator or mass spectrometer.

In a magnetic field, charged particles experience a force that can be used to determine their charge. This force, known as the Lorentz force, is given by the equation F = q(v x B), where F is the force, q is the charge of the particle, v is the velocity of the particle, and B is the strength of the magnetic field.

To determine the charge of a particle in a magnetic field, you can measure the velocity of the particle and the strength of the magnetic field, and then measure the force experienced by the particle. By rearranging the equation F = q(v x B), you can solve for the charge q.

It is important to note that the Lorentz force only applies to charged particles that are in motion. If the particle is stationary, it will not experience any force in a magnetic field.

In practice, there are many ways to measure the charge of a particle in a magnetic field, such as using a particle accelerator or a mass spectrometer. These techniques involve manipulating the motion of the particle in a controlled way and measuring the resulting forces and velocities to determine its charge.

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Complete question:

How can I know the charge of a particle in a magnetic field?

Not far from the mirror showcase (the figure shows a top view) there is a person (indicated by point H in the figure), and closer to the showcase there is a lamppost (point C). By building, find the positions at which the observer (points H, which are indicated for example and are not the answer) will see in the window: a person to the left of the pillar; the person to the right of the pillar; a pole blocking a person

Answers

The observer (point H) must be positioned to the right of the person and to the left of the lamppost, to the left of the person and to the right of the lamppost, or behind the lamppost to see the person obstructed by it.

To determine the possible positions of the observer (point H) relative to the mirror showcase, we need to consider the given information about the position of the person and the lamppost.

If the person is to the left of the lamppost (point C) as seen in the window, then the observer (point H) must be positioned to the right of the person and to the left of the lamppost. This is because the mirror will reflect the image of the person to the right, and the observer must be positioned to the right of the reflected image to see it.

If the person is to the right of the lamppost (point C) as seen in the window, then the observer (point H) must be positioned to the left of the person and to the right of the lamppost. This is because the mirror will reflect the image of the person to the left, and the observer must be positioned to the left of the reflected image to see it.

If the lamppost (point C) obstructs the view of the person as seen in the window, then the observer (point H) must be positioned behind the lamppost, either to the left or to the right of it. This is because the mirror will not be able to reflect the image of the person due to the obstruction caused by the lamppost.

In summary, the possible positions of the observer (point H) relative to the mirror showcase are:

To the right of the person and to the left of the lamppost, to see the person to the left of the lamppost. To the left of the person and to the right of the lamppost, to see the person to the right of the lamppost. To the left or right of the lamppost, behind it, to see the obstruction of the person caused by the lamppost.

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Complete question:

Using the given information, determine the possible positions of the observer (point H) relative to the mirror showcase such that the following are observed:

1 - The person is to the left of the lamppost (point C) as seen in the window.

2 - The person is to the right of the lamppost (point C) as seen in the window.

3 - The lamppost (point C) obstructs the view of the person as seen in the window.

What is wind ? What type of energy is possessed by wind ? (b) Explain how, wind energy can be used to generate electricity. Illustrate your answer with the help of a labelled diagram. (c) State two advantages of using wind energy for generating electricity. (d) Mention two limitations of wind energy for generating electricity

Answers

a) Wind is the movement of air in the Earth's atmosphere. It occurs due to the uneven heating of the Earth's surface by the sun, resulting in the displacement of air from areas of high pressure to areas of low pressure. Wind can occur at various speeds and directions, and it plays a crucial role in weather patterns and climate.

b) Wind energy is a form of kinetic energy that is possessed by the movement of air molecules. This energy can be harnessed to generate electricity through the use of wind turbines.

The process of generating electricity from wind energy involves the following steps:

1. Wind turbines are installed in areas where there is a consistent and strong wind flow. These turbines consist of large blades that are connected to a rotor.

2. When wind flows over the blades, it causes the rotor to spin. The rotation of the rotor generates mechanical energy.

3. This mechanical energy is then converted into electrical energy through the use of a generator.

4. The electrical energy is then transmitted to a power grid, where it can be distributed to homes and businesses.

c) There are several advantages of using wind energy for generating electricity, including:

1. Renewable: Wind energy is a renewable resource, which means it is replenished naturally and can be used indefinitely without depleting natural resources.

2. Clean: Wind energy does not produce harmful pollutants or greenhouse gas emissions, making it a clean and environmentally friendly source of energy.

d) There are also limitations to using wind energy for generating electricity, including:

1. Variability: Wind energy is not a consistent source of energy, as wind speeds can vary depending on weather patterns and time of day. This can make it difficult to rely on wind energy as a sole source of electricity.

2. Land use: Wind turbines require a significant amount of land, which can be problematic in areas with limited space or where wildlife habitats may be affected.

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The observation that individuals from separate species cannot mate to produce offspring is a guideline for identifying _____.

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The observation that individuals from separate species cannot mate to produce offspring is a guideline for identifying distinct species. This criterion is known as the biological species concept.

The biological species concept defines a species as a group of interbreeding organisms that are reproductively isolated from other groups. In other words, individuals within a species can mate and produce viable, fertile offspring, while individuals from different species cannot.

The biological species concept has some limitations. For example, it cannot be applied to asexual organisms or fossils. Additionally, some species can interbreed and produce hybrid offspring, such as the mule, which is a hybrid of a horse and a donkey.

However, these hybrids are often sterile and cannot produce viable offspring of their own, which reinforces the concept that individuals from separate species cannot mate to produce offspring.

Overall, the biological species concept is a useful guideline for identifying distinct species and understanding their evolutionary relationships. It emphasizes the importance of reproductive isolation and genetic divergence in defining separate groups of organisms.

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How old was isaac newton when in 1666 he formulated the theory of universal gravity?

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Isaac Newton was born on January 4, 1643, in England. He was 23 years old when he formulated the theory of universal gravity in 1666.

This was during a period when he was isolating himself to avoid the bubonic plague outbreak that was ravaging England at that time.

While in isolation, Newton engaged in extensive scientific research and discovered the laws of motion, optics, and gravity.

His theory of universal gravitation proposed that every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

This theory revolutionized the field of physics and remains a fundamental concept in modern science.

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What is the physical state of water at 250 degree centigrade

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At 250 degrees Celsius, water is in the gaseous state, specifically as steam or water vapor.

Under normal atmospheric pressure, water boils and undergoes a phase transition from liquid to gas at 100 degrees Celsius. As the temperature increases beyond the boiling point, the water molecules gain enough energy to overcome intermolecular forces and transition into the gaseous state.

Therefore, at 250 degrees Celsius, water exists as a gas or steam rather than as a liquid.

The boiling point of water, where it transitions from liquid to gas, occurs at 100 degrees Celsius at standard atmospheric pressure (1 atmosphere or 101.3 kilopascals). At temperatures below the boiling point, water exists as a liquid.

Therefore, at 250 degrees Celsius, water is well above its boiling point. It would be in the form of a hot liquid rather than a gas. The high temperature causes the water molecules to have greater kinetic energy, resulting in increased movement and a higher average temperature of the liquid.

It's important to note that the state of water can change depending on the pressure. At higher pressures, the boiling point of water increases, and at lower pressures, it decreases.

However, under standard atmospheric pressure, water at 250 degrees Celsius would still remain in the liquid state.

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Determine the force acting downwards on a mass of 1500 g suspended on a string. (14. 72 N)​

Answers

The Force acting downwards on the mass = 14.72N

To determine the force acting downwards on a mass of 1500 g suspended on a string, you'll need to use the formula for gravitational force: F = m * g, where F is the force, m is the mass in kilograms, and g is the acceleration due to gravity (approximately 9.81 m/s²).

First, convert the mass from grams to kilograms: 1500 g = 1.5 kg.

Next, plug the values into the formula: F = 1.5 kg * 9.81 m/s² ≈ 14.72 N.

So, the force acting downwards on the mass is approximately 14.72 N.

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The smallest separation between earth and jupiter is 588 million km while the largest separation is 968 million km. given that jupiter has a physical diameter of 140,000 km, what are the largest and smallest angular sizes of jupiter as seen from earth?

Answers

The largest angular size of Jupiter as seen from Earth is 0.022 degrees and the smallest angular size is 0.013 degrees.

To calculate the angular size of Jupiter as seen from Earth, we can use the formula:
Angular size = [tex](\frac{diameter of object}{distance to object})[/tex]×(180° / π)

For the smallest separation between Earth and Jupiter (588 million km), the angular size of Jupiter would be:
Angular size =[tex](\frac{140,000 km}{588 million km})[/tex]×(180° / π) = 0.022 degrees or approximately 1.3 arcminutes

For the largest separation between Earth and Jupiter (968 million km), the angular size of Jupiter would be:
Angular size = [tex](\frac{140,000 km}{968 million km})[/tex]×(180° / π)= 0.013 degrees or approximately 0.8 arcminutes.

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Wave interference that results in lesser wave amplitude is called.

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Wave interference that results in lesser wave amplitude is called destructive interference. In destructive interference, two waves with opposite phases combine, causing the wave amplitudes to cancel each other out, resulting in a lower overall amplitude.


1. When two waves meet, they can either combine constructively or destructively, depending on their phase relationship.

2. Constructive interference occurs when two waves with the same phase meet, resulting in a greater overall amplitude.

3. Destructive interference occurs when two waves with opposite phases meet, causing the wave amplitudes to cancel each other out, resulting in a lower overall amplitude.

4. This can be observed in various real-life scenarios, such as sound waves, light waves, and water waves.

5. To better understand destructive interference, imagine two waves with the same amplitude and frequency traveling in opposite directions on a string.

6. When the waves meet, the crest of one wave aligns with the trough of the other wave, causing them to cancel each other out.

7. As a result, the string appears to be momentarily flat at the point of destructive interference.

8. Destructive interference plays a crucial role in various applications, such as noise-canceling headphones, which use the concept to cancel out unwanted background noise.

In summary, wave interference that results in lesser wave amplitude is called destructive interference. This phenomenon occurs when two waves with opposite phases meet and cancel each other out, resulting in a lower overall amplitude.

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How much current, in amperes, is in a lightning stroke that lasts 0. 05 second and transfers 100 coulombs

Answers

A lightning strike with a duration of 0.05 seconds and a 100-coulomb energy transfer has a current of 2000 amperes.

The amount of current, in amperes, in a lightning stroke that lasts 0.05 seconds and transfers 100 coulombs can be calculated using the formula I = Q/t, where I represents the current in amperes, Q represents the charge in coulombs, and t represents the time in seconds.

So, substituting the given values in the formula, we get:

I = 100 coulombs / 0.05 seconds

I = 2000 amperes

Therefore, the lightning stroke that lasts 0.05 seconds and transfers 100 coulombs has a current of 2000 amperes. It is important to note that lightning strikes can have varying currents, ranging from tens of thousands to hundreds of thousands of amperes, depending on the size and intensity of the storm. In fact, lightning is one of the most powerful natural phenomena on Earth, capable of generating enormous amounts of energy in just a few microseconds. As such, it is important to take appropriate safety precautions during a lightning storm to minimize the risk of injury or damage.

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With all his gear, Neil Armstrong weighed 360 pounds on Earth. When he landed on the Moon, he weighed 60 pounds. Why?

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Neil Armstrong may have weighed 360 pounds on Earth when he was equipped with all of his gear, but on the moon he only weighed 60 pounds since the moon has less gravitational force (less gravity), thus resulting in less weight. Your weight on the moon is about 1/6th of your weight on Earth. Hope that helps!

Answer: C.

The gravity on the Moon is less than the gravity on Earth.

Explanation: plato :3

A small 350 gram ball on the end of a thin, light rod is rotated horizontal circle of radius 1. 2 m. Calculate a. The moment of inertia of the ball about the center of the circle and b. The torque needed to keep the ball rotating at constant angular velocity if air resistance exerts a force of 0. 020 N on the ball. Ignore air resistance on the rod and it's moment of inertia. ​

Answers

The moment of inertia of a small ball on the end of a thin rod rotating in a horizontal circle of radius 1.2 m is 0.504 kg m². To keep the ball rotating at a constant angular velocity in the presence of air resistance, a torque of 0.024 Nm is needed.

a. The moment of inertia of the ball about the center of the circle is given by I = mr², where m is the mass of the ball and r is the radius of the circle. Substituting the given values, we get I = 0.35 kg x (1.2 m)² = 0.504 kg m².

b. The torque needed to keep the ball rotating at constant angular velocity is given by τ = Iα, where τ is the torque, I is the moment of inertia, and α is the angular acceleration. Since the ball is rotating at a constant angular velocity, α = 0, and the torque needed is zero.

However, air resistance exerts a force on the ball, which tends to slow it down. To counteract this force, an external torque must be applied in the opposite direction.

The magnitude of this torque is given by τ = Fr, where F is the force of air resistance and r is the radius of the circle. Substituting the given values, we get τ = 0.020 N x 1.2 m = 0.024 Nm.

In summary, the moment of inertia of a small ball on the end of a thin rod rotating in a horizontal circle of radius 1.2 m is 0.504 kg m². To keep the ball rotating at a constant angular velocity in the presence of air resistance, a torque of 0.024 Nm is needed.

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Marci drops a ball off the top of the Empire state building. How fast is the ball traveling after 4 seconds? (assuming there is no air)

Answers

Answer:We can use the kinematic equation:

v = vo + at

where:

v = final velocity (what we want to find)

vo = initial velocity (which is zero since the ball is dropped)

a = acceleration due to gravity (-9.8 m/s^2, negative since it is acting in the opposite direction of the ball's motion)

t = time (4 seconds)

Substituting the values, we get:

v = 0 + (-9.8 m/s^2)(4 s)

v = -39.2 m/s

Note that the negative sign indicates that the ball is moving downward.

Explanation:

a 6.00-kg block is in contact with a 4.00-kg block on a horizontal frictionless surface as shown in the figure. the 6.00-kg block is being pushed by a horizontal 20.0-n force as shown. what is the magnitude of the force that the 6.00-kg block exerts on the 4.00-kg block?

Answers

Answer:

Since the surface is frictionless, the only force acting on each block is the force of gravity, which we can ignore for now, and the force exerted by the other block.

We can use Newton's third law, which states that for every action, there is an equal and opposite reaction. Therefore, the force exerted by the 4.00-kg block on the 6.00-kg block is equal in magnitude and opposite in direction to the force exerted by the 6.00-kg block on the 4.00-kg block.

Now, let's focus on the 6.00-kg block. The force acting on it is the 20.0 N force to the right. Since the surface is frictionless, there is no opposing force, and the block accelerates to the right.

We can use Newton's second law, which states that the net force on an object is equal to its mass times its acceleration. Therefore, we have:

Net force = mass x acceleration

20.0 N = 6.00 kg x acceleration

acceleration = 20.0 N / 6.00 kg = 3.33 m/s^2

Now, let's find the force exerted by the 6.00-kg block on the 4.00-kg block. We can use Newton's second law again, this time for the 4.00-kg block:

Net force = mass x acceleration

Force exerted by the 6.00-kg block on the 4.00-kg block = 4.00 kg x acceleration

Force exerted by the 6.00-kg block on the 4.00-kg block = 4.00 kg x 3.33 m/s^2

Force exerted by the 6.00-kg block on the 4.00-kg block = 13.3 N

Therefore, the magnitude of the force that the 6.00-kg block exerts on the 4.00-kg block is 13.3 N.

A car travels at 54 km/h for first 20 s, 36 km/h for next 30 s and finally 18 km/h for next 10 s. Find its average speed.

Answers

39 km/h, or 10.8333 m/s

Explanation:

The average speed is equal to total distance over total time

The formula for distance is s=v×t

So the average speed would be:

v=(v1×t1)+(v2×t2)+(v3×t3)/t1+t2+t3

Now we can solve:

v=(54×20)+(36×30)+(18×10)/60s

v=2340/60

v=39km/h

If you need to convert to m/s, divide by 3.6 and you get 10.8333 m/s

Hope this helps!

Two moles of helium gas initially at 367 K
and 0.6 atm are compressed isothermally to
0.92 atm.
Find the final volume of the gas. Assume
that helium behaves as an ideal gas. The
universal gas constant is 8.31451 J/K · mol.
Answer in units of m3
Find the work done by the gas.
Answer in units of kJ.

Answers

The final volume of the gas, is 0.065 m³.

The work done by the gas is 2.629 kJ.

What is the final volume of the gas?

The final volume of the gas, is calculated as follows;

PV = nRT

where;

P is the pressureV is the volumen is the number of molesR is the universal gas constantT is the temperature

P₁V₁ = P₂V₂

V₁ = (nRT)/P₁

V₁ = (2 mol x 8.31451 J/K·mol x 367 K) / (0.6 atm x 101325 Pa/atm)

V₁ = 0.1 m³

The final volume of the gas is calculated as;

V₂ = (P₁V₁)/P₂

V₂ = (0.6 atm x 0.1) / 0.92 atm

V₂ = 0.065 m³

The work done by the gas is calculated as;

W = -∫PdV

W = -nRT ln(V₂/V₁)

W = -(2 mol  x 8.31451 J/K·mol x 367 K) x ln(0.065/0.1)

W = 2,629 J

W = 2.629 kJ

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If a rocket takes off from earth with a certain force what must be true about earth

Answers

If a rocket takes off from Earth with a certain force, there are several things that must be true about Earth to make this possible.

Firstly, Earth must have a gravitational field that attracts the rocket toward its center. This gravitational force pulls the rocket toward the ground, and the rocket must overcome it with a force greater than the force of gravity in order to take off.

Secondly, Earth's atmosphere must be present, as the rocket needs to push against the air molecules to create thrust and lift off the ground. Thirdly, Earth's surface must be firm enough to support the launch of the rocket, with a strong and stable launchpad to prevent any accidents.

Fourthly, Earth's rotational speed and position in its orbit around the Sun must also be taken into account, as this affects the required trajectory of the rocket for a successful launch. Overall, a combination of Earth's gravitational force, atmosphere, surface conditions, and position in its orbit all play a crucial role in enabling a rocket to take off from Earth.

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Your quadcopter has a terrible altitude sensor. To see how bad it really is you take many measurements with the quadcopter at 1 meter altitude. Your altitude sensor gives a mean of 1. 00 meters with a standard deviation of 13cm. The measurements are normally (Gaussian) distributed. What is the probability that your altimeter gives an error of less than 10cm for a single measurement?

Answers

The altimeter is not very accurate and is likely to have an error of at least 10cm due to high variability in measurements. This is confirmed by the z-score calculation, which shows that a 10cm error is far outside the normal range of variation.

We can use the standard normal distribution to calculate the probability of an error of less than 10cm for a single measurement. First, we need to convert the measurement error of 10cm to a z-score by using the formula:

[tex]z = (x - \mu) / \sigma[/tex]

where x is the measurement error, μ is the mean altitude reading, and σ is the standard deviation.

Substituting the given values, we get:

z = (0.10 - 1.00) / 0.13 = -7.69

Using a standard normal distribution table or calculator, we can find the probability that z is less than -7.69. This probability is essentially zero, which means that it is highly unlikely that the altimeter gives an error of less than 10cm for a single measurement.

In summary, the probability that the altimeter gives an error of less than 10cm for a single measurement is essentially zero.

This is because the mean altitude reading of 1.00 meter and the standard deviation of 13cm indicate a high degree of measurement variability, and the z-score calculation shows that the error of 10cm is far outside the normal range of measurement variation.

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At the gym, a man pulls a bar on a machine that works the muscles of the upper back. It takes him 0. 5 seconds to raise 30


kilograms of weights a vertical distance of 0. 5 meters.


Which of these exerts the same power output? (Estimate g as 10 m/s2. )



A) lifting 25 kilograms a distance of 2. 4 meters in 2. 0 seconds



B) lifting 45 kilograms a distance of 2. 4 meters in 3. 0 seconds


C) leg pressing 45 kilograms a distance of 0. 5 meters in 0. 5 seconds.


D) bench pressing 30 ligrograms a distance of 0. 5 meter in 1. 5 seconds.


Pleaseeeeeee help me

Answers

The power output of the man pulling the bar can be calculated as follows:

Power = Work / Time

The work done by the man is equal to the force he exerts multiplied by the distance he moves the weights:

Work = Force x Distance

The force he exerts is equal to the weight of the weights he is lifting:

Force = Weight x g

where g is the acceleration due to gravity, which is approximately 10 m/s^2.

Plugging in the given values, we get:

Force = 30 kg x 10 m/s^2 = 300 N

Work = Force x Distance = 300 N x 0.5 m = 150 J

Power = Work / Time = 150 J / 0.5 s = 300 W

Now we can check which of the other options exerts the same power output:

Option A:

Force = 25 kg x 10 m/s^2 = 250 N

Work = Force x Distance = 250 N x 2.4 m = 600 J

Power = Work / Time = 600 J / 2.0 s = 300 W

Option B:

Force = 45 kg x 10 m/s^2 = 450 N

Work = Force x Distance = 450 N x 2.4 m = 1080 J

Power = Work / Time = 1080 J / 3.0 s = 360 W

Option C:

Force = 45 kg x 10 m/s^2 = 450 N

Work = Force x Distance = 450 N x 0.5 m = 225 J

Power = Work / Time = 225 J / 0.5 s = 450 W

Option D:

Force = 30 kg x 10 m/s^2 = 300 N

Work = Force x Distance = 300 N x 0.5 m = 150 J

Power = Work / Time = 150 J / 1.5 s = 100 W

Therefore, options A and B exert the same power output as the man pulling the bar, while options C and D do not.

Marshall paddled his kayak 919meters across a lake at a constant velocity. He moved that distance in 10. 0minutes. What was his velocity?

Answers

Marshall's velocity while paddling his kayak across the lake was 1.53 meters per second, which can be calculated by dividing the distance he traveled by the time it took him to cover that distance.

Marshall's velocity can be calculated using the formula:

velocity = distance/time

Where distance is 919 meters and time is 10.0 minutes, which must be converted to seconds:

time = 10.0 minutes = 600 seconds

Substituting these values, we get:

velocity = 919 meters / 600 seconds

velocity = 1.53 meters per second

Therefore, Marshall's velocity was 1.53 meters per second.

To explain this, we can say that velocity is the rate of change of displacement over time, and in this case, Marshall traveled a distance of 919 meters over a period of 10.0 minutes.

By dividing the distance by the time, we can calculate his velocity, which tells us how fast he was traveling in meters per second.

In summary, Marshall's velocity while paddling his kayak across the lake was 1.53 meters per second, which can be calculated by dividing the distance he traveled by the time it took him to cover that distance.

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How far do you have to lift a 10kg bag of salt to do 250j of work?

Answers

You have to lift the 10kg bag of salt approximately 2.55 meters to do 250J of work.

To determine how far you have to lift a 10kg bag of salt to do 250J of work, we need to use the work-energy theorem and the formula for gravitational potential energy. The work-energy theorem states that the work done on an object is equal to the change in its potential energy. The formula for gravitational potential energy is:

PE = m * g * h

where PE is the potential energy, m is the mass (10kg), g is the acceleration due to gravity (approximately 9.8 m/s²), and h is the height the object is lifted.

Since the work done is 250J, we can set the potential energy equal to the work done:

250J = 10kg * 9.8 m/s² * h

Now, we need to solve for h:

250J = 98 kg*m/s² * h
h = 250J / 98 kg*m/s²
h ≈ 2.55 meters

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A simple circuit has a 20 Ω resistor and carries 0. 3 A. What is the voltage of the power source?

Answers

A simple circuit has a 20 Ω resistor and carries 0. 3 A. The voltage of the power source is 6 V.  In a simple circuit with only one resistor, the voltage across the resistor is equal to the voltage of the power source.

Using Ohm's law, we can determine the voltage of the power source by multiplying the resistance (R) of the circuit by the current (I) flowing through it. Thus, we have:

V = IR

Substituting the given values, we get:

[tex]V = (0.3 A)(20\; \Omega) = 6 V[/tex]

Therefore, the voltage of the power source in the circuit is 6 volts. In a simple circuit with only one resistor, the voltage across the resistor is equal to the voltage of the power source.

This is because the sum of the voltages across all the components in the circuit must equal the total voltage of the power source, due to the conservation of energy.

It's important to note that in real-world circuits, the voltage of the power source can fluctuate due to various factors such as fluctuations in the electrical grid or changes in the internal resistance of the power source itself.

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What is the approximate electrostatic force between two protons each having a charge of +1. 6 x 10-19 C separated by a distance of 1. 0 × 10–6 meter?



A)


2. 3 × 10–16 N and repulsive


B)


2. 3 × 10–16 N and attractive


C)


9. 0 × 1021 N and repulsive


D)


9. 0 × 1021 N and attractive

Answers

The approximate electrostatic force between two protons each having a charge of +1. 6 x 10-19 C separated by a distance of 1. 0 × 10–6 meter A) 2.3 × 10^–16 N and repulsive.

To calculate the electrostatic force between two protons, we can use Coulomb's Law:

F = (k * q1 * q2) / r^2

where F is the electrostatic force, k is Coulomb's constant (8.99 × 10^9 N m^2 C^−2), q1 and q2 are the charges of the two protons, and r is the distance between them.

Given: q1 = q2 = +1.6 × 10^-19 C, r = 1.0 × 10^-6 m

Now, plug the values into the formula:

F = (8.99 × 10^9 N m^2 C^−2 * (1.6 × 10^-19 C)^2) / (1.0 × 10^-6 m)^2

F ≈ 2.3 × 10^-16 N

Since both charges are positive, the electrostatic force will be repulsive. Therefore, the correct answer is:

A) 2.3 × 10^–16 N and repulsive

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A 2.0 x 103 kg car is pulled 345 m up a hill that makes an angle of 15 with the horizontal.
a. What is the potential energy of the car at the top of the hill?
b. If the car rolls down the hill, what will its speed be if we neglect friction?

Answers

The potential energy of the car at the top of the hill is 1.75 x 10^6 J. If we neglect friction, the car will have a speed of 74.7 m/s as it rolls down the hill.

a. To find the potential energy of the car at the top of the hill, we need to use the formula:

potential energy = mass x gravity x height

where mass is given as 2.0 x 103 kg, gravity is approximately 9.8 m/s^2, and height is the vertical distance the car is lifted up the hill. We can find this distance by using the angle of 15 and the horizontal distance of 345 m. The vertical distance is given by:

height = 345 m x sin(15) = 90.3 m

Plugging in these values, we get:

potential energy = (2.0 x 103 kg) x (9.8 m/s^2) x (90.3 m) = 1.75 x 10^6 J

So the potential energy of the car at the top of the hill is 1.75 x 10^6 J.

b. To find the speed of the car as it rolls down the hill, we can use the conservation of energy principle:

potential energy at top = kinetic energy at bottom

At the top of the hill, the car has only potential energy, which we found to be 1.75 x 10^6 J. At the bottom of the hill, the car has only kinetic energy, which we can find using the formula:

kinetic energy = 0.5 x mass x velocity^2

where mass is still 2.0 x 103 kg, and velocity is what we are trying to find. Setting the potential energy at the top equal to the kinetic energy at the bottom, we get:

1.75 x 10^6 J = 0.5 x (2.0 x 103 kg) x velocity^2

Solving for velocity, we get:

velocity = sqrt( (2 x 1.75 x 10^6 J) / (2.0 x 103 kg) ) = 74.7 m/s

So if we neglect friction, the car will have a speed of 74.7 m/s as it rolls down the hill.

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A ball of mass 4 kg travelling at 10 m/s makes an elastic head-on collision with another ball of mass 1 kg which is at rest. After the collision, the speed of the lighter ball is
*
zero
less than 10 m/s
equal to 10 m/s
greater than 10 m/s .

Answers

Answer:

less than 10 m/s

Explanation:

The 1 kg ball moves after the elastic collision, so you know its speed is > 0.

Due to the law of conservation of momentum, you know the total momentum before the collision must equal the total momentum after the collision.  Some of the momentum from the 4 kg ball transfers to the 1 kg ball (which is at rest) when they collide.  The 4 kg ball slows down after the collision and the lighter ball moves after the collision, but at a speed less than 10 m/s.

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The acceleration due to gravity g at a distance r from the center of a planet of mass Mis 9 m/s2. In terms of the orbital distance r, what
would the speed of this satellite have to be to remain in a circular orbit around this planet at this distance?
Ov=3/5
v=3r
v=6r
v=9râ

Answers

To stay in a circular orbit at a specific distance, the satellite must have a speed that is three times the square root of that distance. Therefore, the correct answer is option B.

The speed of a satellite in a circular orbit around a planet can be determined by equating the centripetal force required to keep the satellite in orbit with the gravitational force of the planet on the satellite.

The centripetal force is given by [tex]F = mv^2/r[/tex], where m is the mass of the satellite, v is its speed, and r is the distance from the center of the planet.

The gravitational force is given by [tex]F = G(Mm)/r^2[/tex], where G is the gravitational constant, M is the mass of the planet, and m is the mass of the satellite. Equating these two forces and solving for v gives [tex]v = \sqrt{(GM/r)}[/tex]

Substituting the given values for g = 9 m/s² and r, we get [tex]v = \sqrt{(gr)}[/tex], which simplifies to [tex]v = \sqrt{(9r)} = 3\sqrt{r}[/tex].

Therefore, the correct answer is v = 3r. This means that the speed of the satellite must be three times the square root of the distance from the center of the planet to remain in a circular orbit at that distance.

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Jake wants to prove the theorem that says that the measure of the quadrilateral's opposite angles add to 180°

Answers

Jake wants to prove the theorem that states that the measure of the opposite angles of a quadrilateral add up to 180 degrees.

This theorem is also known as the "opposite angles theorem." To prove this, Jake could use several methods, including the use of geometric proofs, algebraic proofs, or even visual aids such as diagrams or sketches.

One way to approach the proof would be to divide the quadrilateral into two triangles and show that the sum of the angles in each triangle equals 180 degrees.

Jake could then use this information to prove that the opposite angles of the quadrilateral add up to 180 degrees as well. Another approach would be to use the properties of parallel lines and transversals to show that the opposite angles are supplementary (i.e., add up to 180 degrees).

Regardless of the method used, the opposite angles theorem is a fundamental concept in geometry that is used to solve a variety of problems involving quadrilaterals.

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