Using the standard convention "positive is up", what is the sign of the acceleration of a rock you throw up (a) as it is going up, and (b) as it is coming back down?

Answer:

Explanation:

What are simple machines?

Simple machines reduce effort or extend the ability to perform tasks beyond their abilities.

Why do we use simple machines?

Simple machines are used widely as they help humans and save time.

Simple Machine Examples:

Answer:

61 m/s

Explanation:

        [tex]v_{f}^{2} - v_{o}^ {2} = 2* g* h (1)[/tex]

Answer:

Thanks!!!!! adding this so it doesn’t get deleted.

Explanation:

1. Electrostatic forces are trillions of times stronger than gravitational forces. 2. normal force and friction 3. contact forces 4. The electrostatic forces from the contact of the hands with the paper causes the paper molecules to separate. 5. The electrostatic forces between the molecules of the board prevent the force of gravity from breaking the board apart.

The correct statement over here is that electrostatic forces are trillions of times stronger than gravitational forces. Hence, option C is correct.

One of the basic forces in the cosmos is electrostatic force. In the universe, there are four basic forces. These include gravitational force, electromagnetic force, weak nuclear force, and strong nuclear force. Under the umbrella of electromagnetic force is electrostatic force. Two charges placed apart are subject to the electrostatic force. The size of each charged and the separation between them determines how much electrostatic force there will be.

When two charges of the same type are brought together, whether positive or negative, they repel one another. It is known as the electrostatic force of repelling when it operates among two charges that are similar.

Therefore, the electrostatic forces are trillions of times stronger than the gravitational forces.

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Answer:

Explanation:

radius of cylinder r₁ = .02 m

radius of safety valve r₂ = .0075 m

force exerted by spring on safety valve = 950 x .0085 = 8.075 N .

Force required on piston of cylinder = F

Applying Pascal's law

8.075 / 3.14 x .0075²  =  F / 3.14 x .02²

F = 8.075 x .02² / .0075²

= 8.075 x 7.111

= 57.42 N .

Thanks for asking your question!

Answer:

D: Sublimation

Explanation:

Sublimation occurs when a substance changes from a solid into a gas. Increases in temperature causes the kinetic energy of particles to also increase. This allows the particles to overcome the intermolecular forces and become mobile. Low pressure also increases the particles' kinetic energy.

Answer:

Injury to a vein increases the risk of forming a blood clot.

Explanation:

hoped this helped

Answer:

Explanation:

a) KE = (1/2) * m * ([tex]v^{2}[/tex]) = F * d = 14m * 200N = 2800 m/N or 2.8 * [tex]10^{3}[/tex] m/N

b) 0J and 0m/s (if Marcella stopped after going 14 meters)

c)  Known from part (a) that KE = 2800 J = F1 * d1,

    2800J = F1 * (14m - 1m)  => F1 = 2800J/13m = 215.384 N

Answer:

35m

Explanation:

25m + 10m = 35m east.

*(adding since it's in the same direction)

Answer:

v₁f = -6.2 cm/s

Explanation:

        [tex]m_{1} *v_{1o} = m_{1}* v_{1f} + m_{2}* v_{2f}[/tex]

       [tex]\frac{1}{2}*m_{1}*v_{1o}^{2} = \frac{1}{2}*m_{1}*v_{1f} ^{2} + \frac{1}2}*m_{2}*v_{2f}^{2}[/tex]

       [tex]v_{1f} = \frac{-m_{1} }{3*m_{1}} *v_{1o} =\frac{-v_{1o}}{3} = -\frac{18.6 cm/s}{3} = -6.2 cm/s[/tex]

Answer:

The rowboat will move away from sally more quickly because the rowboat because the sailboat is larger in mass

Explanation:

Gnerally the row boat will move away from her quicker than the sailboat this is because the mass of the sail boat is larger than the row boat , hence the frictional force that opposes motion will be greater in the sailboat than in the row boat.

Answer:

70-100 BPM

Explanation:

Answer:

The value is  [tex]B =   0.034 \  T [/tex]

Explanation:

From the question we are told that

  The electric field strength is  [tex]E =  2.2*10^{4} \  N/C[/tex]

   The velocity is  [tex]v  = 6.4 *10^{5} \  m/s[/tex]

Generally the magnetic field is mathematically represented as

      [tex]B =  \frac{E}{v}[/tex]

=>    [tex]B =  \frac{2.2*10^{4}}{6.4 *10^{5}}[/tex]

=>    [tex]B =   0.034 \  T [/tex]

Answer:

1.1111.22222

Explanation:

Answer:

The height of the cliff is 121.276 m

Explanation:

Given;

initial velocity of the projectile, v₁ = 75 m/s

final velocity of the projectile, v₂ = 90 m/s

spring compression = 5 m

Apply the law of conservation of energy;

mgh₀ + ¹/₂mv₁² = mgh₂ + ¹/₂mv₂²

gh₀ + ¹/₂v₁² = gh₂ + ¹/₂v²

gh₁  - gh₂ = ¹/₂v₂² - ¹/₂v₁²

g(h₀  - h₂) = ¹/₂ (v₂² - v₁²)

h₀  - h₂ = ¹/₂g (v₂² - v₁²)

h₀ = h(cliff) + 5m

when the projectile hits the ground, Final height, h₂ = 0

[tex]h_o - 0 = \frac{1}{2g}(v_2^2-v_1^2)\\\\h_{cliff} + 5= \frac{1}{2g}(v_2^2-v_1^2)\\\\h_{cliff} = \frac{1}{2g}(v_2^2-v_1^2) - 5\\\\h_{cliff} = \frac{1}{2*9.8}(90^2-75^2) - 5\\\\h_{cliff} = 121.276 \ m[/tex]

Therefore, the height of the cliff is 121.276 m

Answer:

Distance 20 km and Displacement 0 km

His displaceent is 0 km because he ends his walk where he started. The total distance of his walk is 20 km because he walks 10 km to the store + 10km back home.

Answer:

Philosophy is a study that involves the nature of knowledge and truth. It serves as a guide that helps an individual seek which things are valuable and essential in life. ... It gives you a sense of direction, knowing the weight of things, therefore making you more productive.

Answer:

K and I

Explanation:

Contour maps use lines that represent spaces in a map that have the same elevation, this means that all the lines should be continuous and closed, in this case, we are not able to see the full extent of most of the lines, but since the points are located in different lines we can assume that they are at different heights, so since only point K and point I are on the same line, we know that these two points are at the same height.

Answer:

51.2Joules

Explanation:

Work done = Force × distance

Force = mg = 64.5×9.81

Force = 632.745N

Next is to get the distance using the equation of motion

v² = u²+2gS

1.26² = 0+2(9.81)S

1.5876 = 19.62S

S = 1.5876/19.62

S = 0.0809m

Get the work done:

Work done = F×S

Work done = 632.745×0.0809

Work done = 51.2Joules

Hence the net work done in Joules is 51.2Joules

The net work done required to stop a crate will be "51.2 Joules".

According to the question,

Mass, m = 64.5 kg

Speed, v = 1.26 m/s

Acceleration due to gravity, g = 9.8

We know,

The force, F = mg

By substituting the values,

                    = 64.5 × 9.8

                    = 632.745 N

By using Equation of motion,

→       v² = u² + 2gS

 (1.26)² = 0 + 2(9.81) S

1.5876 = 19.62 S

         S = [tex]\frac{1.5876}{19.62}[/tex]

            = 0.0809 m  

hence,

The work done (W) will be:

= F × S

= 632.745 × 0.0809

= 51.2 Joules

Thus the above response above is correct.

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Answer:

23.44444444

Explanation:

Insurance is an example of benefits therefore the corrct answer is option D.

The exercise has a beneficial effect on the body and differs the type of death a person undergoes. If a person exercises but sits for too long can result in many diseases that ultimately lead to death. Along with exercise, the person should do mobile activities so that it increases their fitness.

It is among the most notable and significant advantages of insurance. According to insurance plans, the insured person or companies are protected from liabilities. The correct kind of insurance coverage might help you protect yourself from losses brought on by various life uncertainty.

Insurance is a good example of a benefit because, unlike salaries, which are things you earn as a base when you start a job, benefits are things you only receive as a result of working in certain jobs.

Thus,the correct answer is option D.

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Answer:

6000 joules

Explanation:

I jus learned dis

Answer:6000j

Explanation:

Hope that helps

Answer:

Explanation:

The total distance is how far you walk from the starting point.

Distance through west = 18.0m

Distance through north = 25.0m

Total distance covered = 18.0+25.0m

Total distance covered = 43.0m

This means that I am 43.0m from the starting point

Displacement is the distance covered in a specified direction. The displacement will be gotten using the Pythagoras theorem as shown:

[tex]d^2 = 25^2 + 18^2\\d^2 = 625+324\\d^2 = 949\\d = \sqrt{949}\\ d = 30.81m[/tex]

The direction of your displacement is 30.81m

Direction is gotten according to the formula;

[tex]\theta = tan ^{-1}{\frac{y}{x} }\\\theta = tan ^{-1}{\frac{25}{-18} }\\\theta = tan ^{-1}-1.3889}\\\theta = -60.27^0\\\theta = 180-60.27\\\theta = 119.7^0[/tex]

Note that the direction to the west is negative, that is why the x is -18.0m

The distance from the starting point is 43 m, the displacement vector is 30.81 m and the direction of the displacement is 119.7 degrees.

Given-

Distance travel through the west is 18 m.

Distance travel through the north is 25 m.

To know the total distance, add both the covered distance. Thus total distance x is,

[tex]x=18+25[/tex]

[tex]x=43[/tex]

Hence, the distance from the starting point is 43 m.

Displacement is calculated as the shortest distance between starting and final point. This shortest distance can be calculated using the Pythagoras theorem which states that in a right-angled triangle, the square of the hypotenuse [tex]d[/tex] is equal to the sum of the squares of the other two sides. Therefore,

[tex]d^2=18^2+25^2[/tex]

[tex]d^2=324+625[/tex]

[tex]d^2=949[/tex]

[tex]d=\sqrt{949}[/tex]

[tex]d=30.81[/tex]

The displacement vector is 30.81 m.

The direction of displacement [tex]\theta[/tex] with these two sides can be calculated with the formula,

[tex]\theta=tan^{-1}\dfrac{25}{-18}[/tex]

Here due to the west direction(opposite side), the sign is taken negatively.

[tex]\theta=tan^{-1}(-1.389)[/tex]

[tex]\theta=-60.27^o[/tex]

For the other quarter,

[tex]\theta=180-60.27=119.7^o[/tex]

Hence, the distance from the starting point is 43 m, the displacement vector is 30.81 m and the direction of the displacement is 119.7 degrees.

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Answer:

can exchange energy with its surroundings through heat and work transfer. In other words, work and heat are the forms that energy can be transferred across the system boundary.

Answer:

Explanation:

Find the diagram attached for the schematic diagram of motion of the cart. The displacement of the cart is the length AD.

To get the length AD, we will apply Pythagoras theorem on ΔAED.

According to the theorem:

AD² = AE²+ED²

AD² = 20²+15²

AD² = 400+225

AD² = 625

AD = √625

AD = 25.0m

Hence the shopper’s total displacement is 25.0m

Answer:

The number of electrons entering the thin wire every second is 1.75 x 10⁻³ mobile electrons / second

Explanation:

Given;

emf of the battery, V = 1.5 V

electron density, = 9 × 10²⁸ mobile electrons per m³

mobility of electron, u = 7 × 10⁻⁵ (m/s)/(N/C)

length of thin wire, L = 6 cm = 0.06 m

cross sectional area of the thin wire, A = 1.3 x 10⁻⁸ m²

The magnitude of the electric field in the thin wire is given by;

E = V/L

E = (1.5) / (0.06)

E = 25 N/C

the number of electrons entering the thin wire every second is given by;

[tex]e/s = mobility \ x \ Electric \ field\\\\number \ of \ electrons \ per \ second =\frac{7*10^{-5} (m/s)}{N/C} *25 (N/C)\\\\number \ of \ electrons \ per \ second = 1.75*10^{-3} \ m/s[/tex]

Therefore, the number of electrons entering the thin wire every second is 1.75 x 10⁻³ mobile electrons / second

The number of electrons entering the thin wire every second is 1.75 x 10⁻³ mobile electrons / second

Since

emf of the battery, V = 1.5 V

electron density, = 9 × 10²⁸ mobile electrons per m³

mobility of electron, u = 7 × 10⁻⁵ (m/s)/(N/C)

length of thin wire, L = 6 cm = 0.06 m

cross sectional area of the thin wire, A = 1.3 x 10⁻⁸ m²

So here the magnitude should be

E = V/L

E = (1.5) / (0.06)

E = 25 N/C

Now the number of electrons should be

= 7 × 10⁻⁵  *25

= 1.75 x 10⁻³ mobile

hence, The number of electrons entering the thin wire every second is 1.75 x 10⁻³ mobile electrons / second

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Answer:

skeletal,cardiac,and smooth.

Explanation:

Answer:

Skeletal, smooth, and cardiac.

Explanation:

Skeletal Muscles:

Skeletal muscles are the most familiar type of muscles; they make up most of the muscle mass in the body. Flexible bands of connective tissue called tendons attach these muscles to the bones in the body. Skeletal muscles control voluntary movement in the body.

Smooth Muscles:

Smooth muscles are involuntary muscles that we don’t consciously control. They are found within the walls of many organs and control the movement of these organs. For example, they enable the movement of food through the digestive system.

Cardiac Muscles:

Cardiac muscles are a special type of involuntary muscle. Located in the heart, these muscles control the contractions of the heart.

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Answer:

Just to help, periods on the periodic table are those running horizontally from left to right

Answer:

The answer is A.Boron and carbon are likely together in one period because they have very close atomic numbers, while gallium and germanium are likely together in another period because they have very close atomic numbers.

Explanation:

just took test

Answer:

Explanation:

(a) The force of gravity is called an attractive force because it is the force (although weak) in which a planetary body or matter uses to attract an object towards itself.

(b) Yes, it does and the formula for force of gravity between any two object is

F = G[tex]\frac{m1m2}{r}[/tex]

where m1 and m2 are masses of the first and second object respectively

r is the distance between the center of the two masses

G is the gravitational constant

Answer:

The length of the spring is 44.92 cm

Explanation:

Hooke's Law

Suppose a spring of constant k and natural length x0. If a force F is applied to the spring and it stretches to a distance x1. Hooke's Law states that:

[tex]F=k.x[/tex]

Where x is the elongation of the spring:

[tex]x=x1-x0[/tex]

We are given the characteristics of a spring of x0=31 cm. When a mass of m=8 Kg is hung from the spring, it stretches to x1=36.9 cm. We need to calculate the force of the mass of 8 Kg. It can be done by calculating the weight:

[tex]F = m.g=8\ Kg\cdot 9.8\ m/s^2[/tex]

[tex]F=78.4\ N[/tex]

The elongation of the spring is

[tex]x=36.9\ cm - 31\ cm = 5.9\ cm[/tex]

Converting to meters:

[tex]x=5.9/100=0.059\ m[/tex]

(a)

From Hooke's Law, we solve for k:

[tex]\displaystyle k=\frac{F}{x}=\frac{78.4}{0.059}[/tex]

[tex]k=1,329\ N/m[/tex]

(b) With the value of k, the equation for the spring is:

[tex]F=1,329.x[/tex]

Now if a weight of F=185 N is hung from the spring, the elongation is:

[tex]\displaystyle x=\frac{F}{1,329}=\frac{185}{1,329}[/tex]

[tex]x=0.1392\ m=13.92\ cm[/tex]

Thus, the length of the spring is:

[tex]x1=xo+x=31\ cm+13.92\ cm=44.92\ cm[/tex]

The length of the spring is 44.92 cm

(a)The spring constant will be 1,329 N/m.

(b)The length of the spring will be 44.92 cm.

Spring constant is defined as the ratio of force per unit displaced length. The spring force is balanced by the weight;

The given data in the problem is;

L₁  is the long spring is hung vertically from a ceiling= 31.0 cm

L₂  = 36.9 cm

m is the mass= 8.00 kg

The net elongation of the spring is

x= 36.9-31 =5.9 cm = 0.059 m

The force acted on the spring due to which the elongation is done;

F=mg

F= 8 × 9.81

F=78.4 n

From the Hooke's law the spring constant is found as;

[tex]\rm K = \frac{F}{x} \\\\ \rm K = \frac{78.4}{0.059} \\\\ \rm K = 1,329 \ N/m[/tex]

Hence the spring constant will be 1,329 (in N/m).

(b) The length of the spring will be 44.92 cm.

For the  weight of F=185 N is hung from the spring, the elongation is:

[tex]\rm x= \frac{185}{1,329} \\\\ \rm x=0.10392 m = 13.92 \ cm[/tex]

The length of spring is;

[tex]\rm x_1 = x_0+x \\\\ \rm x_1 = 31+13.92 \\\\ \rm x_1=44.92\ cm[/tex]

Hence the length of the spring will be 44.92 cm.

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