Energy and Momentum

An upward force is applied to a 6.0–kilogram box. This force displaces the box upward by 10.00 meters. What is the work done by the force on the box?

A.
6.0 × 10^1 joules
B.
-6.0 × 10^1 joules
C.
5.9 × 10^2 joules
D.
-5.9 × 10^2 joules

What is the value of work done on an object when a 0.1x10^2–newton force moves it 30 meters and the angle between the force and the displacement is 25°?

A.
2.7 × 10^2 joules
B.
3.0 × 10^2 joules
C.
7.5 × 10^2 joules
D.
0 joules

In which situation is the maximum possible work done?

A.
when the angle between the force and displacement is 0°
B.
when the angle between the force and displacement is 180°
C.
when the angle between the force and displacement is 45°
D.
when the angle between the force and displacement is 90°

Roger pushes a box on a 30° incline. If he applies a force of 60 newtons parallel to the incline and displaces the box 10 meters along the incline, how much work will he do on the box?

A.
5.2 × 10^2 joules
B.
6.0 × 10^2 joules
C.
-5.2 × 10^2 joules
D.
-6.0 × 10^2 joules

What is the value of work done on an object when a 70–newton force moves it 9.0 meters in the same direction as the force?

A.
7.8 joules
B.
6.3 × 10^2 joules
C.
-7.8 joules
D.
0 joules

In which situation is no work being done?

A.
a person carrying a box from one place to another
B.
a person picking up a box from the ground
C.
a person pushing a box from one place to another
D.
a person pulling a box from one place to another

What is the value of work done on an object when a 50–newton force moves it 15 meters in the same direction as the force?

A.
435 joules
B.
97.3 joules
C.
750 joules
D.
693 joules

Anne releases a stone from a height of 2 meters. She measures the kinetic energy of the stone at 9.8 joules at the exact point it hits the ground. What is the mass of the stone?

A.
0.5 kilograms
B.
0.6 kilograms
C.
0.4 kilograms
D.
0.9 kilograms

Julie is cycling at a speed of 3.4 meters/second. If the combined mass of the bicycle and Julie is 30 kilograms, what is the kinetic energy?

A.
1.7 × 10^2 joules
B.
1.5 × 10^2 joules
C.
2.0 × 10^2 joules
D.
2.2 × 10^2 joules

Jim is playing with a 1–meter–long pendulum that is hooked 2 meters above the ground. He lifts the pendulum's bob to a height of 2 meters above the ground and then releases it. Potential energy is assigned zero value at the ground level. Which statement is true about this problem?

A.
At the lowest position of the bob, the KE is equal to zero.
B.
At the highest position of the bob, the PE is equal to zero.
C.
At the highest position of the bob, the KE is equal to zero.
D.
At all the positions except the highest positions, the PE is zero.

A bob of mass of 0.18 kilograms is released from a height of 45 meters above the ground level. What is the value of the kinetic energy gained by the bob at the ground level?

A.
250 joules
B.
51 joules
C.
79 joules
D.
8.1 joules

An object with a mass of 100 grams (0.100 kg) is dropped from a certain height and has a velocity of 60 meters/second. If the potential energy of this object is 179.99 joules, how high was the object when it was dropped?

A.
9.2 × 10^1 meters
B.
1.8 × 10^2 meters
C.
9.8 × 10^2 meters
D.
1.0 × 10^2 meters

What form of energy transforms to what other form when you turn on a steam iron?

A.
electrical energy to potential energy
B.
electrical energy to kinetic energy
C.
electrical energy to chemical energy
D.
electrical energy to thermal energy

A ball having a mass of 500 grams is dropped from a height of 9.00 meters. What is its kinetic energy when it hits the ground?

A.
4.4 × 10^3 joules
B.
441 joules
C.
44.1 joules
D.
4.41 joules

In which device is chemical energy transformed into electrical energy?

A.
battery
B.
hair dryer
C.
television
D.
hydroelectric plant

A motorist driving at 25 meters/second decelerates to 15 meters/second. The combined mass of the vehicle and the driver is 1.5 × 10^3 kilograms. What is the amount of mechanical work done by the vehicle?

A.
7.5 × 10^4 joules
B.
1.5 × 10^5 joules
C.
3.0 × 10^5 joules
D.
6.2 × 10^5 joules

A truck accelerating at 0.0083 meters/second^2 covers a distance of 5.8 × 10^4 meters. If the truck's mass is 7,000 kilograms, what is the work done to reach this distance?

A.
1.7 × 10^6 joules
B.
3.4 × 10^6 joules
C.
5.6 × 10^6 joules
D.
6.8 × 10^6 joules

What is the main difference between the formulas for kinetic energy (KE) and gravitational potential energy (PE)?

A.
KE depends on position and PE depends on motion.
B.
KE depends on motion and PE depends on position.
C.
Both energies depend on motion, but only KE depends on position.
D.
Both energies depend on position, but only PE depends on motion.

What is the difference between the energy of spring A, stretched 0.6 meters, and spring B, stretched 0.3 meters, if they have the same spring constant?

A.
Spring A has more potential energy than spring B.
B.
Spring A has less potential energy than spring B.
C.
Springs A and B have the same potential energy.
D.
Springs A and B have the same kinetic energy.

In Hooke's law, if a large force produces a small displacement, what does that say about the spring?

A.
k is small.
B.
k is large.
C.
The spring is soft.
D.
The spring is long.

If the period of a spring is 5 seconds, what is the frequency?

A.
25 hertz
B.
2.5 hertz
C.
0.2 hertz
D.
20 hertz

When is the restoring force of a spring equal to zero?

A.
at the stretched position
B.
at the minimum displacement
C.
at the equilibrium position
D.
at the compression position

Which statement best compares momentum and kinetic energy?

A.
Both momentum and kinetic energy are vector quantities.
B.
Momentum is a vector quantity and kinetic energy is a scalar quantity.
C.
Kinetic energy is a vector quantity and momentum is a scalar quantity.
D.
Both momentum and kinetic energy are scalar quantities.

What is the momentum of a 35–kilogram cart moving at a speed of 1.2 meters/second?

A.
42 kilogram·meters/second
B.
70 kilogram·meters/second
C.
4.2 × 10^2 kilogram·meters/second
D.
7.0 × 10^2 kilogram·meters/second

Which statement best compares momentum and kinetic energy?

A.
If you double the velocity of an object, its kinetic energy doubles. But for the same increase in velocity, the momentum increases four times.
B.
If you double the velocity of an object, its momentum doubles. But for the same increase in velocity, the kinetic energy increases four times.
C.
If you double the velocity of an object, its momentum and kinetic energy doubles.
D.
If you double the velocity of an object, its momentum and kinetic energy increases four times.

The momentum of an object depends on which two quantities?

A.
velocity and weight
B.
mass and kinetic energy
C.
velocity and kinetic energy
D.
mass and velocity

What is the mass of a stone moving at a speed of 15 meters/second and having a momentum of 7.5 kilogram·meters/second?

A.
0.5 kilograms
B.
1.5 kilograms
C.
11 kilograms
D.
1.1 × 10^2 kilograms

A large mass collides with a stationary, smaller mass. How will the masses behave if the collision is inelastic?

A.
They will collide and then separate.
B.
They will stick to each other and move together.
C.
The larger mass will stop and the smaller mass will start moving.
D.
The two masses will bounce off each other and move in opposite directions.

When a speeding truck hits a stationary car, the car is deformed and heat is generated. What can you say about the kinetic energy of the system after the collision?

A.
The kinetic energy of the system is conserved.
B.
The kinetic energy of the system is partially used for deforming the car.
C.
The kinetic energy of the system is not responsible for deforming the car.
D.
The kinetic energy of the system is completely transformed to heat energy.

A solid plastic ball hits a stationary tennis ball in a perfectly elastic collision. If the mass of the plastic ball is three times that of the tennis ball, which statement is true?

A.
The two balls separate but continue to move in the same direction.
B.
The two balls stick and move together.
C.
The plastic ball stops and the tennis ball starts moving.
D.
The plastic ball moves backward.

Bodies A and B have equal mass. Body B is initially at rest. Body A collides with body B in a one–dimensional elastic collision. Which statement is true?

A.
Body A comes to rest. Body B starts moving with the initial velocity of body A.
B.
The momentum of the system is not conserved.
C.
The kinetic energy of the system is not conserved.
D.
The final velocity of body B is twice the initial velocity of body A.

A car with a mass of 1.5 × 10^3 kilograms is traveling west at a velocity of 22 meters/second. It hits a stationary car with a mass of 9.0 × 10^2 kilograms. If the collision is inelastic, what is the final direction and approximate velocity of the two cars?

A.
14 meters/second to the west
B.
14 meters/second to the east
C.
22 meters/second to the east
D.
22 meters/second to the west