Q: Work in physics is defined as:

$$\mathrm{Force \times Distance}$$

Question 1

A moving car does not carry force, but it does carry which physical quantity?

Accepted Answer

Momentum

Question 2

Which of the following is the correct unit for momentum?

Accepted Answer

$$\mathrm{kg\cdot m/s}$$

Question 3

According to the law of conservation of linear momentum, in the absence of external forces, the total momentum of a system before a collision is:

Accepted Answer

Equal to after the collision

Question 4

Impulse is defined as:

Accepted Answer

Change in momentum

Question 5

A 2 kg ball moving at $$3\ \mathrm{m/s}$$ collides with a stationary 2 kg ball. If the collision is perfectly elastic and there are no external forces, what is the total momentum of the system after the collision?

Accepted Answer

$$6\ \mathrm{kg\cdot m/s}$$

Question 6

Which of the following quantities is the same for both a bug and a car during a head-on collision?

Accepted Answer

All of the above

Question 7

Work in physics is defined as:

Accepted Answer

$$\mathrm{Force 	imes Distance}$$

Question 8

If you lift a barbell that is twice as heavy the same distance, how much work do you do compared to lifting the original barbell?

Accepted Answer

Twice as much

Question 9

A lifting force is used to raise a $$2\ \mathrm{N}$$ block $$4\ \mathrm{m}$$ vertically. How much work was done by the lifting force?

Accepted Answer

$$8\ \mathrm{J}$$

Question 10

Which of the following is an example of gravitational potential energy?

Accepted Answer

A ball held at a height $$h$$ above the ground

Question 11

The formula for gravitational potential energy is:

Accepted Answer

$$PE = mgh$$

Question 12

Kinetic energy is always:

Accepted Answer

Positive

Question 13

If the speed of an object is doubled, its kinetic energy:

Accepted Answer

Quadruples

Question 14

Which statement is true about momentum and kinetic energy?

Accepted Answer

Momentum is a vector, kinetic energy is a scalar

Question 15

A ball rolling down a frictionless incline has its maximum kinetic energy at:

Accepted Answer

The bottom

Question 16

The work-kinetic energy theorem states:

Accepted Answer

$$\mathrm{Work = \Delta KE = KE_f - KE_i}$$

Question 17

If the initial speed of a car is doubled, the stopping distance required (assuming constant friction force) is:

Accepted Answer

Four times as much

Question 18

You push a crate horizontally with a $$100\ \mathrm{N}$$ force across a $$10\ \mathrm{m}$$ factory floor. If the force of friction is $$70\ \mathrm{N}$$, what is the kinetic energy gained by the crate?

Accepted Answer

$$300\ \mathrm{J}$$

Question 19

A ramp allows you to move a cart with less force but more distance. The total work done in moving the cart up the ramp is:

Accepted Answer

Independent of the ramp's steepness

Question 20

When the wind speed doubles, the power produced by a wind turbine:

Accepted Answer

Is eight times greater

module 4 lecture 8: Momentum, Energy, Work, and Simple Machines

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