Question 1

Which of the following statements best describes a conservative force?

Accepted Answer

The work it does on an object moving between two points is independent of the path taken.

Question 2

A ball of mass $$m is $$dropped from a height $$h$$ above the ground. Ignoring air resistance, what is the work done by gravity as the ball falls to the ground?

Accepted Answer

$$W = mgh$$

Question 3

Which of the following is NOT a conservative force?

Accepted Answer

Friction force

Question 4

A spring with spring constant $$k is $$compressed by a distance $$x$$ from its equilibrium position. What is the elastic potential energy stored in the spring?

Accepted Answer

$$U = \frac{1}{2}kx^2$

Question 5

A 2 kg object is lifted vertically from $$y_0 = 0$ m to y = 5$ m. What is the change in gravitational potential energy? (Take g = 9.8$ m/s^2$)

Accepted Answer

$$\Delta U = 49 J$$

Question 6

Which equation correctly expresses the conservation of mechanical energy for a system with only conservative forces?

Accepted Answer

$$K + U = 	ext{constant}$$

Question 7

A block slides down a frictionless incline. Which of the following statements is true about its mechanical energy?

Accepted Answer

Mechanical energy is conserved because only conservative forces act.

Question 8

A 0.5 kg mass is attached to a spring with $$k = 200 N/m $$and is compressed by 0.1 m. What is the elastic potential energy stored in the spring?

Accepted Answer

$$U = 1 J$$

Question 9

A person jumps off a bridge with a bungee cord attached. At the lowest point of the jump, which form of energy is maximized?

Accepted Answer

Elastic potential energy

Question 10

If friction is present, which of the following statements about mechanical energy is correct?

Accepted Answer

Mechanical energy is not conserved; some is transformed into other forms such as heat.

Question 11

A roller coaster car of mass $$m$$ starts from rest at height $$h$$ and descends to a lower height $$h_2$$ with negligible friction. What is its speed at $$h_2$$?

Accepted Answer

$$v = \sqrt{2g(h - h_2$)}$$

Question 12

Which of the following best describes the work done by a nonconservative force?

Accepted Answer

It is path dependent and often dissipates energy as heat or sound.

Question 13

A student compresses a spring and releases it, launching a ball upward. Which energy transformation occurs as the ball rises?

Accepted Answer

Elastic potential energy to kinetic energy to gravitational potential energy

Question 14

Which formula gives the change in gravitational potential energy when an object moves from $$y_0 to$$ $$y$$?

Accepted Answer

$$\Delta U = mg(y - y_0$)$$

Question 15

A person runs up a hill, doing positive work against friction. How does this affect the total mechanical energy of the system?

Accepted Answer

Total mechanical energy increases due to the positive nonconservative work.

Question 16

Which of the following is true about potential energy curves?

Accepted Answer

They plot potential energy as a function of position and can be used to analyze motion.

Question 17

A trampoline jumper lands and compresses the trampoline, then rebounds upward. Which principle best explains the energy transformation?

Accepted Answer

Conservation of mechanical energy, including elastic potential energy

Question 18

A block slides across a rough surface and comes to rest. What happens to its initial mechanical energy?

Accepted Answer

It is transformed into thermal energy due to friction.

Question 19

Which equation correctly relates the change in mechanical energy to work done by nonconservative forces?

Accepted Answer

$$\Delta E = W_{nc}$$

Question 20

A ball is thrown upward with initial speed $$v_0. At $$its highest point, which statement is true?

Accepted Answer

Its kinetic energy is zero and its gravitational potential energy is maximized.

Potential Energy and Conservation of Energy: Study Notes

스터디 가이드 - 연습 문제

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