Q: A 2 kg object moves in a circle of radius 3 m at a constant speed of 4 m/s. What is the magnitude of the centripetal force acting on the object?

$$F_c = \frac{mv^2$}{r} = \frac{2 \times 16}{3} = 10.67\ \text{N}$$

Q: A projectile is launched at an angle $$\theta$$ with initial speed $$v_0. $$What is the time of flight before it lands back at the same height?

$$t = \frac{2v_0 \sin \theta}{g}$$

Q: A 5 kg object is dropped from a height of 10 m. What is its velocity just before hitting the ground? (Assume $$g = 9.8\ \text{m/s}^2)$$

$$v = \sqrt{2gh} = \sqrt{2 \times 9.8 \times 10} \approx 14\ \text{m/s}$$

Q: A 3 kg object is moving at 5 m/s. What is its kinetic energy?

$$KE = \frac{1}{2}mv^2$ = \frac{1}{2} \times 3 \times 25 = 37.5\ \text{J}$$

Q: A 10 kg box is pulled across a rough surface with a force of 50 N at an angle of $$30^\circ$$ above the horizontal. What is the horizontal component of the force?

$$F_x = 50 \cos 30^\circ = 43.3\ \text{N}$$

Q: A 0.2 kg ball is attached to a string and swung in a horizontal circle of radius 0.5 m at a speed of 3 m/s. What is the tension in the string?

$$T = \frac{mv^2$}{r} = \frac{0.2 \times 9}{0.5} = 3.6\ \text{N}$$

Q: A 1 kg object is dropped from rest and falls for 2 seconds. What is its velocity after 2 seconds? (Assume $$g = 9.8\ \text{m/s}^2)$$

$$v = gt = 9.8 \times 2 = 19.6\ \text{m/s}$$

Question 1

A block of mass $$m$$ slides down a frictionless incline of height $$h. $$What is its speed at the bottom of the incline?

Accepted Answer

$$v = \sqrt{2gh}$$

Question 2

Which of the following best describes the work done by a constant force $$\vec{F}$$ acting over a displacement $$\vec{d}$$?

Accepted Answer

$$W = Fd \cos 	heta$$

Question 3

A car of mass $$m$$ traveling at velocity $$v$$ comes to a stop over a distance $$d$$ due to a constant braking force $$F. $$What is the magnitude of the braking force?

Accepted Answer

$$F = \frac{mv^2$}{2d}$$

Question 4

A ball is thrown vertically upward with initial velocity $$v_0. $$What is the maximum height reached by the ball?

Accepted Answer

$$h_{max} = \frac{v_0$^2}{2g}$$

Question 5

A 2 kg object moves in a circle of radius 3 m at a constant speed of 4 m/s. What is the magnitude of the centripetal force acting on the object?

Accepted Answer

$$F_c = \frac{mv^2$}{r} = \frac{2 	imes 16}{3} = 10.67\ 	ext{N}$$

Question 6

Which of the following is the correct expression for the period $$T of a $$simple pendulum of length $$L$$?

Accepted Answer

$$T = 2\pi \sqrt{\frac{L}{g}}$$

Question 7

A projectile is launched at an angle $$	heta$$ with initial speed $$v_0. $$What is the time of flight before it lands back at the same height?

Accepted Answer

$$t = \frac{2v_0 \sin 	heta}{g}$$

Question 8

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

Accepted Answer

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

Question 9

A 5 kg object is dropped from a height of 10 m. What is its velocity just before hitting the ground? (Assume $$g = 9.8\ 	ext{m/s}^2)$$

Accepted Answer

$$v = \sqrt{2gh} = \sqrt{2 	imes 9.8 	imes 10} \approx 14\ 	ext{m/s}$$

Question 10

Which of the following statements about conservation of energy is correct?

Accepted Answer

The total energy of an isolated system remains constant over time.

Question 11

A 0.5 kg ball moving at 6 m/s collides elastically with a stationary 0.5 kg ball. What is the velocity of the first ball after the collision?

Accepted Answer

$$v_1$$' = 0\ 	ext{m/s}$$

Question 12

A force $$F is $$applied to a mass $$m$$ for a time $$t. $$What is the change in momentum of the mass?

Accepted Answer

$$\Delta p = Ft$$

Question 13

A satellite orbits Earth in a circular orbit of radius $$r. $$What is the expression for its orbital speed?

Accepted Answer

$$v = \sqrt{\frac{GM}{r}}$$

Question 14

Which of the following is the correct expression for the gravitational potential energy between two masses $$m_1$$ and $$m_2$$ separated by a distance $$r$$?

Accepted Answer

$$U = -\frac{Gm_1m_2}{r}$$

Question 15

A 3 kg object is moving at 5 m/s. What is its kinetic energy?

Accepted Answer

$$KE = \frac{1}{2}mv^2$ = \frac{1}{2} 	imes 3 	imes 25 = 37.5\ 	ext{J}$$

Question 16

A 10 kg box is pulled across a rough surface with a force of 50 N at an angle of $$30^\circ$$ above the horizontal. What is the horizontal component of the force?

Accepted Answer

$$F_x = 50 \cos 30^\circ = 43.3\ 	ext{N}$$

Question 17

A 0.2 kg ball is attached to a string and swung in a horizontal circle of radius 0.5 m at a speed of 3 m/s. What is the tension in the string?

Accepted Answer

$$T = \frac{mv^2$}{r} = \frac{0.2 	imes 9}{0.5} = 3.6\ 	ext{N}$$

Question 18

A 1 kg object is dropped from rest and falls for 2 seconds. What is its velocity after 2 seconds? (Assume $$g = 9.8\ 	ext{m/s}^2)$$

Accepted Answer

$$v = gt = 9.8 	imes 2 = 19.6\ 	ext{m/s}$$

Physics Final Exam Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드