Answer:
Explanation:
O.20 hour A
If a car is traveling at an average speed of 70 kilometers per hour, 0.2 hours it takes the car to travel 14 kilometers.
What is average speed?By multiplying the distance that an item travels in one unit by the amount of time it takes to go that distance, one may determine the speed of the object. The speed of the item on this voyage, denoted by the letter "s," is equal to s = D/T if "D" is indeed the distance traveled in certain time "T."
Understanding average speed will help you better comprehend the pace of a travel. On a travel, the pace could occasionally change. Knowing the average speed then becomes crucial to getting an idea of how quickly the route will be finished.
Distance covered = average speed × Time travelled
14=70× Time travelled
Time travelled = 0.2 hours
Therefore, 0.2 hours it takes the car to travel 14 kilometers.
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A 925 N crate is being pulled across a level floor
by a force F of 325 N at an angle of 25 above the
horizontal. The coefficient of kinetic friction is
0.25. Find the magnitude of the acceleration of
the crate.
The magnitude of the acceleration of the crate is 1.033 m/s².
The given parameters;
weight of the crate, W = 925 Nhorizontal force applied to the carte, F = 325 Nangle of inclination of the force, θ = 25⁰the coefficient of friction, μ = 0.25The mass of the crate is calculated as;
W = mg
[tex]m = \frac{W}{g} \\\\m = \frac{925}{9.8} \\\\m = 94.388 \ kg[/tex]
The normal force on the crate is calculated as;
Fₙ = 925 - 325 x sin(25)
Fₙ = 925 - 137.35
Fₙ = 787.65 N
The frictional force on the object is calculated as follows;
[tex]F_k = \mu F_n\\\\F_k = 0.25 \times 787.65\\\\F_k = 196.91 \ N[/tex]
The magnitude of the crates acceleration is calculated from the net horizontal force on the crate;
[tex]\Sigma F_x = 0\\\\Fcos (\theta) - F_k = ma\\\\325\times cos(25) \ - \ 196.91 = ma\\\\97.54 = ma[/tex]
[tex]a = \frac{97.54}{94.388} \\\\a = 1.033 \ m/s^2[/tex]
Thus, the magnitude of the acceleration of the crate is 1.033 m/s².
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a jogger travels at 4 m/s for 100 s what is the distance covered
400m
Explanation:
given,
v= 4m/s
t= 100s
d= ?
since, v = d / t
therefore, d = v * t (velocity multiplied by time)
=> d = 4 * 100
= 400m.
cameron drives his car 15 km north. He stops for lunch and then drives 12 km south. What is his displacement?
Answer:
Displacement is 3 km North
Explanation:
Increase in potential energy of spring
What are the standard international (si) units of distance
Answer:
meter
Explanation:
Answer: The International System of Units is a system of measurement based on 7 base units
Explanation: the metre, kilogram, second, ampere, Kelvin, mole, and candela. These base units can be used in combination with each other.
The cross sectional area of Sphere 2 is increased to 3 times the cross sectional area of Sphere 1. The masses remain 1.0 kg and 9.0 kg, The terminal speed (in m/s) of Sphere 2 will now be:______
Complete question is;
a. Two equal sized and shaped spheres are dropped from a tall building. Sphere 1 is hollow and has a mass of 1.0 kg. Sphere 2 is filled with lead and has a mass of 9.0 kg. If the terminal speed of Sphere 1 is 6.0 m/s, the terminal speed of Sphere 2 will be?
b. The cross sectional area of Sphere 2 is increased to 3 times the cross sectional area of Sphere 1. The masses remain 1.0 kg and 9.0 kg, The terminal speed (in m/s) of Sphere 2 will now be
Answer:
A) V_t = 18 m/s
B) V_t = 10.39 m/s
Explanation:
Formula for terminal speed is given by;
V_t = √(2mg/(DρA))
Where;
m is mass
g is acceleration due to gravity
D is drag coefficient
ρ is density
A is Area of object
A) Now, for sphere 1,we have;
m = 1 kg
V_t = 6 m/s
g = 9.81 m/s²
Now, making D the subject, we have;
D = 2mg/((V_t)²ρA))
D = (2 × 1 × 9.81)/(6² × ρA)
D = 0.545/(ρA)
For sphere 2, we have mass = 9 kg
Thus;
V_t = √[2 × 9 × 9.81/(0.545/(ρA) × ρA))]
V_t = 18 m/s
B) We are told that The cross sectional area of Sphere 2 is increased to 3 times the cross sectional area of Sphere 1.
Thus;
Area of sphere 2 = 3A
Thus;
V_t = √[2 × 9 × 9.81/(0.545/(ρA) × ρ × 3A))]
V_t = 10.39 m/s
a car is moving eastward and speeding up. the momentum of the car is
An 80-kg bungee jumper jumps off a bridge. Rubber bungee cords act as a large spring attaching the jumper to the bridge. A bear standing in the river below catches the jumper. If the spring constant of the bungees is 20 N/m and they stretch 50 m. How much force must the bear apply to keep the jumper from moving?
Answer:
The force is [tex]F_b = 216 \ N [/tex]
Explanation:
From the question we are told that
The mass of the bungee jumper is m = 80 kg
The spring constant is [tex]k = 20 \ N/ m[/tex]
The extension of the rubber bungee cords is x = 50 m
Generally the weight of the jumper is
[tex]W = m * g[/tex]
=> [tex]W = 80 * 9.8 [/tex]
=> tex]W = 784 \ N [/tex]
Generally the returning force of the rubber bungee cords is mathematically represented as
[tex]F = k * x[/tex]
=> [tex]F = 20 * 50 [/tex]
=> [tex]F = 1000 \ N [/tex]
The force to be applied by the bear is
[tex]F_b = F - W[/tex]
=> [tex]F_b = 100 - 784[/tex]
=> [tex]F_b = 216 \ N [/tex]
A bus starts off with a speed of 20 m/s. It is moving in a direction that is 41 degrees from due east (positive numbers being counter-clockwise). After 20 seconds the bus' speed is 45 m/s and it is now moving in a direction that is 56 degrees from due east. What is the angle in degrees of the vector that represents the change in the velocity of the bus
Answer:
[tex]tan^{-1}[/tex] ( 24.19 / 10.06 )
Explanation:
starting speed = 20m/s
direction = 41 degrees from due east
after 20 seconds
bus speed = 45m/s
direction = 56 degrees from due east
calculate the angle of the vector that represents the change in the velocity of the bus
change in velocity : ΔV = Vf - Vi
Vf = Vf ( cos βi + sinβj )
= 45m/s ( cos 56 i + sin56 j )
= 25.16 i + 37.31 j
Vi = Vi ( cos ∝ i + sin ∝ j )
= 20 m/s ( cos 41 i + sin 41 i )
= 15.10 i + 13.12j
Hence the change in velocity ΔV ( Vf - Vi )
= 10.06 i + 24.19 j
the angle in degrees ( ∅ ) = [tex]tan^{-1}[/tex] ( 24.19 / 10.06 )
An object from a certain height falls freely. which of the following happens PE and KE when the object is half on its way down
Answer:
A. Loses PE and gains KE
Explanation:
Statement is incomplete. Complete statement of problem is:
1. An object from a certain height falls freely. Which of the following happens to PE and KE when the object is half on its way down?
A. Loses PE and gains KE
B. Gains PE and loses KE
C. Loses both PE and KE
D. Gains both PE and KE
If we neglect the effects of any conservative force, the application of the Principle of Energy Conservation is reduced to a sum of gravitational potential ([tex]U_{g}[/tex]) and translational kinetic energies, measured in joules. That is:
[tex]U_{g,1}+K_{1} =U_{g,2}+K_{2}[/tex] (Eq. 1)
Let assume that an object falls from a height [tex]h[/tex] with a speed of zero. By definitions of gravitational potential and translational kinetic energies the previous is expanded. If final height is the half of initial value, then:
[tex]m\cdot g\cdot h = 0.5\cdot m\cdot g\cdot h +K_{2}[/tex] (Eq. 1b)
[tex]K_{2} = 0.5\cdot m\cdot g\cdot h[/tex]
[tex]K_{2} = 0.5\cdot U_{g,1}[/tex]
In a nutshell, translational kinetic energy is increased at the expense of diminishing gravitational potential energy. The correct answer is A.
A box falls out of an airplane that is traveling horizontally at 100m/s. The plane is at an altitude of 300m.
Where does the box land relative to where it was dropped from?
Answer:
782.461 m
Explanation:
[tex]a_{x}=0[/tex] [tex]v_{xo}=100[/tex] [tex]a_{y}=-g[/tex] [tex]v_{yo}=0[/tex]
X-direction | Y-direction
[tex]x=x_{o}+v_{xo}t[/tex] | [tex]y=y_{o}+v_{yo}t+\frac{1}{2} a_{y} t^2[/tex]
[tex]x=100(7.82461)[/tex] | [tex]0=300-\frac{1}{2}(9.8)t^2[/tex]
x= 782.461 m | [tex]-300=-4.9t^2[/tex]
| [tex]\sqrt{\frac{-300}{-4.9} } =\sqrt{t^2}[/tex]
| [tex]7.82461=t[/tex]
The box is falling due the attraction of gravitational force (its weight) and it lands at approximately 782.1 meters further from where it was dropped
The reason why the above value of the location is correct is given as follows:
The known parameter of the box are;
Horizontal velocity of the box, vₓ = 100 m/s
The altitude of the plane, h = 300 m
Required:
The location where the box lands
Solution:
The time it takes the box to land is [tex]t =\sqrt{\dfrac{2 \cdot h}{g} }[/tex]
Where;
g = The acceleration due to gravity ≈ 9.81 m/s²
Therefore;
[tex]t =\sqrt{\dfrac{2 \times 300}{9.81} } \approx 7.821[/tex]
The time it takes the box to reach the ground, t ≈ 7.82 seconds
Horizontal distance covered by the by the box during free fall, d, = The distance the box lands relative to where it was dropped from and is given as follows;
d = vₓ × t
∴ d ≈ 100 m/s × 7.821 s = 782.1 m
Therefore;
The distance the box lands relative to where it was dropped from d ≈ 782.1 m
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Question 1-1: In each case, lifting or pushing, why must you exert a force to keep the object moving at a constant velocity?
Answer:
We must apply a force to keep the object moving at a constant velocity due to gravitational force or weight (in case of lifting), and due to frictional force (in case of pushing).
Explanation:
LIFTING:
When an object is lifted, we first need to overcome the force exerted on it by the field of gravity. Due to this force, which is also called the weight of object, we must apply a force on the object to keep it moving at constant speed, otherwise the gravity force will cause the object to slow down and eventually fall back on ground.
PUSHING:
When pushing an object the person must apply the force to first overcome the frictional force. The frictional force acts in opposite direction of motion. Thus, to move the object at constant speed we must apply force to it.
Hence, we must apply a force to keep the object moving at a constant velocity due to gravitational force or weight (in case of lifting), and due to frictional force (in case of pushing).
A helicopter accelerates at a rate of 7 m/s2 for 5 seconds. Calculate its velocity if it's final velocity is 60 m/s.
Answer:
7 m/s
Explanation:
Answer: 25 m/s
Explanation:
Use formula acceleration = velocity final - velocity initial divided by time
A = 7 m/s^2
Vf = 60 m/s
Vi =
t = 5 sec
7 = 60 - x/5
Multiply both sides by 5
35 = 60 - x
Subtract 60 from both sides
-25 = -x
x = 25
Vi = 25 m/s
What is the difference between em waves and mechanical waves?
Answer:
Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space.
Explanation:
Since electromagnetic waves do not require a medium to pass through, they are faster in matter that has fewer particles. ... ~ Sound cannot travel in a vacuum because mechanical waves, such as sound waves, require a medium to propagate through.
use the hubble's law to determine the distance to a quasar receding at 75% the speed of light. The speed of light is 300,000 km/sec. assume Hubble's constant is
Complete question:
use the hubble's law to determine the distance to a quasar receding at 75% the speed of light. The speed of light is 300,000 km/sec. assume Hubble's constant is 2.2 x 10⁻⁵ km/s/Lyr
Answer:
The distance to the quasar is 1.02 x 10¹⁰ Lyr
Explanation:
Given;
speed of light, v = 300, 000 km/sec
Hubble's constant, H₀ = 2.2 x 10⁻⁵ km/s/Lyr
percentage of the quasar recession = 75% of speed of light
Hubble's Law is given by;
[tex]v =H_od\\\\d = \frac{v}{H_o}\\\\d= \frac{(0.75*300,000)}{2.2*10^{-5}}.Lyr\\\\d = 1.02*10^{10} \ Lyr[/tex]
Therefore, the distance to the quasar is 1.02 x 10¹⁰ Lyr
A researcher is interested in exploring the effects of exposure to ultraviolet light on people’s emotional state. He divides his participants into three groups. The first group receives 40 minutes of ultraviolet light 3 times a week, the second group receives 20 minutes of ultraviolet light 3 times a week, and the third group receives no ultraviolet light. Tell me which group(s) were in the control group, and which were in the experimental group. (You can simply delete the incorrect answer for each group. So, for example, if you think the answer to group one is "control," you can simply delete the word "experimental" after group one)
Group One: Experimental Control
Group Two: Experimental Control
Group Three: Experimental Control
Answer:
Explanation:
In an experimental research, the control group is the group that serves as the neutral group that is not given any form of treatment and serves as the group in which the experimental groups are firstly compared to. Thus, the control group in the question described is the Third group.
While experimental groups are the groups that receive treatments required to make an inference from the experiment. From this description, it can be deduced that the First and the Second group are the experimental groups.
A small compass is held horizontally, the center of its needle has a distance of 0.270 m directly north
of a long wire that is perpendicular to the Earth's surface. When there is no current in the wire, the
compass needle points due north, which is the direction of the horizontal component of the Earth's
magnetic field at that location. This component is parallel to the Earth's surface. When the current in
the wire is 26.3 A, the needle points 22.9∘ east of north.
(a) Does the current in the wire flow toward or away from the Earth's surface? ( 2 marks)
(b) What is the magnitude of the horizontal component of the Earth's magnetic field at the location of
the compass? (3 marks)
Answer:
Explanation:
The needle is showing north south direction . when current starts flowing in the wire which is held vertical to the ground , it deflects towards east .
a )
Therefore a magnetic field towards east has been created . It is possible only if current flows towards the surface in the vertical wire .
b )
magnetic field created at the magnetic needle B = 10⁻⁷ x 2I / d where I is current and d is distance .
B = 10⁻⁷ x 2 x 26.3 / .27
= 194.81 x 10⁻⁷ T
angle of deflection of solenoid = 22.9°
Tan 22.9 = B /H
.422 = 194.81 x 10⁻⁷ / H
H = 461.63 x 10⁻⁷ T
= .46 x 10⁻⁴ T .
A) The current in the wire flows towards the Earth's surface
B) The magnitude of the horizontal component of the Earth's magnetic field is : 0.46 x 10⁻⁴ T
A) The compass needle held horizontally points in a North-south direction of the earth and also deflects eastwards when current is allowed to flow through it. The deflection of the needle indicates the presence/generation of a magnetic field on the earth surface. which is facilitated by the flow of the current in the wire towards the Earth's surface
B) Determine The magnitude of the horizontal component of the Earth's magnetic field
B ( magnetic field ) = 10⁻⁷ * 2I / d ---- ( 1 )
where : l = 26.3 A, d = 0.27 m
Back to equation ( 1 )
B = 10⁻⁷ * 2 * 26.3 / 0.27
= 194.81 * 10⁻⁷ T
Final step : Calculate the magnitude of horizontal component ( H )
Tan ∅ = B / H ---- ( 2 )
where : ∅ ( angle of deflection ) = 22.9°
∴ H = B / Tan ( 22.9° )
= ( 194.81 * 10⁻⁷ ) / 0.422
= 0.46 x 10⁻⁴ T
Hence we can conclude that The current in the wire flows towards the Earth's surface and The magnitude of the horizontal component of the Earth's magnetic field is : 0.46 x 10⁻⁴ T
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Anything that takes up space and has mass is
a. Volume
b. Density
C. Matter
d. Viscous
Answer:
materia
Explanation:
Answer:
the answer to your question is matter
Write a general expression for the force that the spring exerts on the mass, in term of k and x. Choose the initial position of the front of the spring to be xi
Complete Question
The complete question is shown on the first uploaded image
Answer:
The value is [tex]F_{spring} = - k * x_f[/tex]
Explanation:
Generally the force exerted on the mass by the spring is mathematically represented as
[tex]F_{spring} = - k * \Delta x[/tex]
Here the negative sign shows that the force is acting in the negative x axis
k is the spring constant
and [tex]\Delta x[/tex] is the distance through which the spring moves the mass which is mathematically evaluated as
[tex]\Delta x = x_f -x_i[/tex]
=> [tex]F_{spring} = - k * [ x_f -x_i][/tex]
Given that [tex]x_i = 0 \ m[/tex]
[tex]F_{spring} = - k * x_f[/tex]
21. Prediction: If you were to measure the current at points A, B and C, how do you think the values would compare? Why? 22. Prediction: If you were to measure the potential differences across these bulbs (what the voltmeter measures) how do you think the values will compare to each other and to the potential difference across the battery pack or the power supply? Why?
Answer:
hello your question is incomplete attached below is the complete question
21) The current at points B and C would be the same ( identical bulbs) while the current at Point A will be greater than the currents at point B and C. i.e. twice the current at either point B or point C
22) The potential difference across the bulbs will be the same and this is because the bulbs are connected in parallel to the the power source ( battery)
hence the voltage in the battery will be equal to the voltage across each bulb
Explanation:
The current at points B and C would be the same ( identical bulbs) while the current at Point A will be greater than the currents at point B and C. i.e. twice the current at either point B or point C
The potential difference across the bulbs will be the same and this is because the bulbs are connected in parallel to the the power source ( battery)
hence the voltage in the battery will be equal to the voltage across each bulb
Plz help me fast WITH EXTRA POINTS AFTER SUBMITTING
Answer:
4 bobux
Explanation:
one bobux
two bobux
three bobux
four bobux
A yo-yo is made of two solid cylindrical disks, each of mass 0.055 kg and diameter 0.070 m , joined by a (concentric) thin solid cylindrical hub of mass 0.0055 kg and diameter 0.011 m . Part A Use conservation of energy to calculate the linear speed of the yo-yo when it reaches the end of its 1.1 m long string, if it is released from rest. Express your answer using three significant figures and include the appropriate units.
Answer: IM 95%sure that the answer is B jus took the test got the answer right
Explanation:
Answer:
sorry I forgot I wish I could help
Sophia pushes with a 40-N horizontal force on a 4.0-kg box resting on a lab bench. The box slides against a horizontal friction force of 24 N. show that the box acceleration at 4.0 m/s2
Answer:
a = 4.0 m / s², so the result of the exercise is correct
Explanation:
This is an exercise on Newton's Second Law
F = m a
we create a reference system with the horizontal x axis and the vertical y axis
Axis y
N -W = 0
X axis
F -fr = m a
give us the applied force F = 40 N, the value of the friction outside fr = 24 N
a = (F - fr) / m
let's calculate
a = (40 - 24) / 4
a = 4.0 m / s²
so the result of the exercise is correct
A student must design an experiment to determine the relationship between the mass of an object and the resulting acceleration when the object is under the influence of a net force. Which of the following experiments should the student conduct in order to determine the relationship between all three quantities?
Answer choices:
A) Drop objects of different masses from a known height above the ground for multiple trials such that they reach their respective terminal speeds. Use a stopwatch to measure the time it takes each object to reach the ground, and record the mass of each object by using a mass scale.
B) Slide objects of different masses across the same rough surface so that each object travels at a constant speed while under the influence of the force of kinetic friction. Then measure the force required to keep each object at a constant speed by using a force sensor, and record the mass of each object by using a mass scale. Perform this experiment multiple times with objects of different masses.
C) Place an object on a rough surface so that the object is at rest. Use a force sensor to exert a force on the object until just after the object overcomes the force of static friction. Record this force. Repeat the experiment for objects of different masses.
D) Slide an object of known mass across a rough surface, using a constant applied force that can be measured by a force sensor. Place a motion detector behind the object so that its speed can be measured as it slides across the surface. Repeat the experiment for different applied forces.
Answer:
D) Slide an object of known mass across a rough surface, using a constant applied force that can be measured by a force sensor. Place a motion detector behind the object so that its speed can be measured as it slides across the surface. Repeat the experiment for different applied forces.
Explanation:
"The motion detector will provide information about the object’s speed as a function of time as it slides as a result of the applied force. The information about the object’s speed as a function of time can be used to determine the acceleration of the object. The force sensor measures the applied force exerted on the object, and the mass of the object is known. Therefore, this experiment can be used to determine how an object’s mass is related to the net force exerted on the object and the acceleration of the object."
It cannot be A because we need an acceleration will be determined by gravity.
It cannot be B because the term constant speed means that there is no net force, which is required by the initial question.
It cannot be C because the experiment is good for determining the coefficient of friction but not for determining how the mass relates to the acceleration.
It must be D because the object is moving and we have a motion detector, we can graph the acceleration vs time graph. So D allows you to have a lot of the different acceleration values which helps with determining the relationship between acceleration and the mass.
What is the term for the cumulative body of observations on which scientific explanations are based?
peer review
pseudoscience
logical reasoning
empirical evidence
On cold winter mornings, Ellen's mother will frequently put a space heater in the kitchen. The space heater has coils that use electrical energy to make heat. When the heater is turned on, the coils glow bright orange and heat the room. What types of energy are given off by the space heater?
Answer:
C
Explanation:
It seems right.
answer
Think of it this way. Osmosis occurs when water flows to a different side given its a membrane or not. This is because it flows to a less dense area to reach equilibrium between the two sides. Heat is very similar. It will try to spread to places where there is not as much heat. Keeping the laws of heat travels up, the heat from the coils will reach the ends. We call this "Thermal Equilibrium"
A shell is fired with a horizontal velocity in the positive x direction from the top of an 80 m high cliff. The shell strikes the ground 1330 m from the base of the cliff. What is the speed of the shell as it hits the ground
Answer:
V = 331.59m/s
Explanation:
First we need to calculate the time taken for the shell fire to hit the ground using the equation of motion.
S = ut + 1/2at²
Given height of the cliff S = 80m
initial velocity u = 0m/s²
a = g = 9.81m/s²
Substitute
80 = 0+1/2(9.81)t²
80 = 4.905t²
t² = 80/4.905
t² = 16.31
t = √16.31
t = 4.04s
Next is to get the vertical velocity
Vy = u + gt
Vy = 0+(9.81)(4.04)
Vy = 39.6324
Also calculate the horizontal velocity
Vx = 1330/4.04
Vx = 329.21m/s
Find the magnitude of the velocity to calculate speed of the shell as it hits the ground.
V² = Vx²+Vy²
V² = 329.21²+39.63²
V² = 329.21²+39.63²
V² = 108,379.2241+1,570.5369
V² = 109,949.761
V = √ 109,949.761
V = 331.59m/s
Hence the speed of the shell as it hits the ground is 331.59m/s
If it takes you 5 minutes to dry your hair using a 1200-W hairdryer plugged into a 120-V power outlet, how many Coulombs of charge pass through your hair dryer
Answer:
The charge pass through your hair dryer is 3000 C.
Explanation:
Given that,
Power = 1200 W
Voltage = 120 V
Flow time = 5 min
We need to calculate the current
Using formula of power
[tex]P=VI[/tex]
[tex]I=\dfrac{P}{V}[/tex]
Put the value into the formula
[tex]I=\dfrac{1200}{120}[/tex]
[tex]I=10\ A[/tex]
We need to calculate the charge pass through your hair dryer
Using formula of current
[tex]I=\dfrac{Q}{t}[/tex]
[tex]Q=It[/tex]
Put the value into the formula
[tex]Q=10\times5\times60[/tex]
[tex]Q=3000\ C[/tex]
Hence, The charge pass through your hair dryer is 3000 C.
Which of the following is a homogeneous mixture?
a.
salad
b.
vegetable soup
c.
salt water
d.
oil & water
Explanation: (Two liquids can have a very close boiling point) So it will be salt water. I think :C
What is the cause of space
Answer:
this depends on religion
Explanation:
some people believe in the big bang and some people believe in Jesus Christ and other gods.
big bang- Gravity
God- spoke
