Q: A 1 kg object is moving at $$10\ \text{m/s}. $$What is its momentum?

$$p = 10\ \text{kg} \cdot \text{m/s}$$

Q: A 1.5 kg object is moving at $$4\ \text{m/s}. $$What is its momentum and kinetic energy?

$$p = 6\ \text{kg} \cdot \text{m/s}$$, $$KE = 12\ \text{J}$$

Question 1

A 2 kg object is lifted vertically from the ground to a height of 5 m. What is the gravitational potential energy gained by the object? (Assume $$g = 9.8\ 	ext{m/s}^2)$$

Accepted Answer

$$PE = 98\ 	ext{J}$$

Question 2

Which of the following statements best describes the Law of Conservation of Energy?

Accepted Answer

Energy cannot be created or destroyed; it can only be transferred or transformed.

Question 3

A student pushes a box with a force of $$20\ 	ext{N}$$ over a distance of $$3\ 	ext{m}. $$How much work is done on the box?

Accepted Answer

$$W = 60\ 	ext{J}$$

Question 4

If a car’s speed doubles, by what factor does its kinetic energy change?

Accepted Answer

It becomes four times as great.

Question 5

Which of the following is a non-conservative force?

Accepted Answer

Friction

Question 6

A 0.5 kg ball is thrown straight up with a speed of $$8\ 	ext{m/s}. $$What is its initial kinetic energy?

Accepted Answer

$$KE = 16\ 	ext{J}$$

Question 7

A person climbs a staircase and does $$500\ 	ext{J} of $$work in $$10\ 	ext{s}. $$What is their average power output?

Accepted Answer

$$P = 50\ 	ext{W}$$

Question 8

Which formula correctly expresses the work-energy theorem?

Accepted Answer

$$W_{	ext{net}} = \Delta KE$$

Question 9

A spring is compressed and stores $$15\ 	ext{J} of $$potential energy. When released, it launches a ball that receives $$12\ 	ext{J} of $$kinetic energy. What happened to the remaining energy?

Accepted Answer

It was transformed into heat due to friction.

Question 10

Which of the following statements about kinetic energy and momentum is correct?

Accepted Answer

Kinetic energy is a scalar, while momentum is a vector.

Question 11

A 1 kg object is moving at $$10\ 	ext{m/s}. $$What is its momentum?

Accepted Answer

$$p = 10\ 	ext{kg} \cdot 	ext{m/s}$$

Question 12

A 3 kg object is dropped from a height of $$4\ 	ext{m}. $$What is its speed just before hitting the ground? (Assume $$g = 9.8\ 	ext{m/s}^2$$ and ignore air resistance.)

Accepted Answer

$$v = 8.9\ 	ext{m/s}$$

Question 13

Which scenario best illustrates the transformation of potential energy into kinetic energy?

Accepted Answer

A ball rolling down a ramp.

Question 14

If a person pushes against a wall that does not move, how much work is done on the wall?

Accepted Answer

Work is zero.

Question 15

A 2 kg object is moving at $$5\ 	ext{m/s}. $$What is its kinetic energy?

Accepted Answer

$$KE = 50\ 	ext{J}$$

Question 16

Which of the following is NOT a form of mechanical energy?

Accepted Answer

Thermal energy

Question 17

A 4 kg object is lifted to a height of $$2\ 	ext{m}$$ and then dropped. What is its speed just before hitting the ground? (Assume $$g = 9.8\ 	ext{m/s}^2)$$

Accepted Answer

$$v = 6.3\ 	ext{m/s}$$

Question 18

A 1.5 kg object is moving at $$4\ 	ext{m/s}. $$What is its momentum and kinetic energy?

Accepted Answer

$$p = 6\ 	ext{kg} \cdot 	ext{m/s}$$, $$KE = 12\ 	ext{J}$$

Question 19

A 5 kg object is moving at $$2\ 	ext{m/s}. If $$its speed increases to $$4\ 	ext{m/s}$$, what is the change in kinetic energy?

Accepted Answer

$$\Delta KE = 30\ 	ext{J}$$

Chapter 7: Energy – Physics with Calculus Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard