Q: A car of mass $$1000 \ \mathrm{kg} is $$moving at $$20 \ \mathrm{m/s}. $$What is its kinetic energy?

$$KE = 2 \times 10^5$ \ \mathrm{J}$$

Question 1

A 2 kg object is lifted vertically by 5 meters. What is the work done by gravity during this process? (Take $$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$W = -98 \ \mathrm{J}$$

Question 2

Which of the following best describes the principle of conservation of energy?

Accepted Answer

Energy cannot be created or destroyed, only transformed from one form to another.

Question 3

A car of mass $$1000 \ \mathrm{kg} is $$moving at $$20 \ \mathrm{m/s}. $$What is its kinetic energy?

Accepted Answer

$$KE = 2 	imes 10^5$ \ \mathrm{J}$$

Question 4

Which equation correctly expresses the work-energy theorem?

Accepted Answer

$$W = \Delta KE$$

Question 5

A 0.5 kg ball is dropped from a height of 10 m. Ignoring air resistance, what is its velocity just before hitting the ground?

Accepted Answer

$$v = \sqrt{2gh} = 14 \ \mathrm{m/s}$$

Question 6

Which of the following is NOT a method of heat transfer?

Accepted Answer

Compression

Question 7

A gas is compressed in a cylinder, and its internal energy increases. Which of the following statements is true?

Accepted Answer

Work is done on the gas by the surroundings.

Question 8

A 3 kg object moving at $$4 \ \mathrm{m/s}$$ collides elastically with a stationary 2 kg object. What is the total momentum before the collision?

Accepted Answer

$$p = 12 \ \mathrm{kg \cdot m/s}$$

Question 9

Which of the following best describes an inelastic collision?

Accepted Answer

Objects stick together after collision.

Question 10

A rotating disk has a moment of inertia $$I$$ and angular velocity $$\omega. $$What is its rotational kinetic energy?

Accepted Answer

$$KE_{rot} = \frac{1}{2} I \$$omega^2$$

Question 11

A 1 kg block slides down a frictionless incline from a height of 5 m. What is its speed at the bottom?

Accepted Answer

$$v = \sqrt{2gh} = 9.9 \ \mathrm{m/s}$$

Question 12

Which of the following is a correct statement about internal energy?

Accepted Answer

Internal energy includes both kinetic and potential energies at the microscopic level.

Question 13

A 0.2 kg ball moving at $$3 \ \mathrm{m/s}$$ collides with a 0.3 kg ball at rest. If they stick together, what is their final velocity?

Accepted Answer

$$v = 1.2 \ \mathrm{m/s}$$

Question 14

Which of the following scenarios best illustrates the conservation of momentum?

Accepted Answer

A rocket expelling gas in space and moving in the opposite direction.

Question 15

A metal rod is heated at one end. Which process primarily transfers heat to the other end?

Accepted Answer

Conduction

Question 16

A spinning figure skater pulls in her arms and spins faster. Which principle explains this?

Accepted Answer

Conservation of angular momentum

Question 17

Which formula gives the gravitational potential energy of an object of mass $$m at $$height $$h$$?

Accepted Answer

$$PE = mgh$$

Question 18

A 5 kg object moving at $$2 \ \mathrm{m/s}$$ collides with a 3 kg object moving at $$-1 \ \mathrm{m/s}. $$What is the total momentum after the collision if the system is isolated?

Accepted Answer

$$p = 7 \ \mathrm{kg \cdot m/s}$$

Question 19

Which of the following is true about elastic collisions?

Accepted Answer

Both kinetic energy and momentum are conserved.

Question 20

A 2 kg object is moving in a circle of radius 3 m at a constant speed of $$4 \ \mathrm{m/s}. $$What is its angular momentum?

Accepted Answer

$$L = mvr = 24 \ \mathrm{kg \cdot m^2$/s}$$

Physics Study Guide: Work, Energy, Momentum, and Rotational Motion (Chapters 6-9)

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