Q: A ball is thrown vertically upward with an initial velocity of $$15\ \mathrm{m/s}. $$Neglecting air resistance, what is the maximum height reached by the ball? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

$$h = \frac{v^2$}{2g} = \frac{(15)^2$}{2 \times 9.8} = 11.5\ \mathrm{m}$$

Q: A 5 kg box is pulled across a horizontal surface with a constant force of 20 N. If the coefficient of kinetic friction is $$\mu_k = 0.2$$, what is the acceleration of the box? ($$g = 9.8\ \mathrm{m/s^2$})$$

$$a = \frac{F - f_k}{m} = \frac{20 - (0.2 \times 5 \times 9.8)}{5} = 1.44\ \mathrm{m/s^2$}$$

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

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

Q: A 3 kg object moving at 2 m/s collides inelastically with a 2 kg object at rest. What is the final velocity of the combined mass?

$$v_f = \frac{m_1v_1 + m_2v_2}{m_1$ + m_2$} = \frac{3 \times 2 + 2 \times 0}{3 + 2} = 1.2\ \mathrm{m/s}$$

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?

$$T = \frac{mv^2$}{r} = \frac{0.2 \times 3^2$}{0.5} = 3.6\ \mathrm{N}$$

Q: A spring with spring constant $$k = 200\ \mathrm{N/m} is $$compressed by 0.1 m. What is the elastic potential energy stored in the spring?

$$U = \frac{1}{2}kx^2$ = \frac{1}{2} \times 200 \times (0.1)^2$ = 1\ \mathrm{J}$$

Q: A projectile is launched at an angle $$\theta$$ with initial speed $$v_0. $$What is the maximum range on level ground?

$$R = \frac{v_0$^2 \sin 2\theta}{g}$$

Question 1

A car accelerates uniformly from rest to a speed of 20 m/s in 10 seconds. What is the car's acceleration?

Accepted Answer

$$a = \frac{20\ \mathrm{m/s}}{10\ \mathrm{s}} = 2\ \mathrm{m/s^2$}$$

Question 2

Which of the following best describes Newton's First Law of Motion?

Accepted Answer

An object at rest remains at rest and an object in motion remains in motion unless acted upon by a net external force.

Question 3

A ball is thrown vertically upward with an initial velocity of $$15\ \mathrm{m/s}. $$Neglecting air resistance, what is the maximum height reached by the ball? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$h = \frac{v^2$}{2g} = \frac{(15)^2$}{2 	imes 9.8} = 11.5\ \mathrm{m}$$

Question 4

A 5 kg box is pulled across a horizontal surface with a constant force of 20 N. If the coefficient of kinetic friction is $$\mu_k = 0.2$$, what is the acceleration of the box? ($$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$a = \frac{F - f_k}{m} = \frac{20 - (0.2 	imes 5 	imes 9.8)}{5} = 1.44\ \mathrm{m/s^2$}$$

Question 5

A satellite orbits Earth in a circular path with radius $$r. $$Which equation gives the speed $$v of $$the satellite?

Accepted Answer

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

Question 6

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

Accepted Answer

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

Question 7

Which of the following statements about work is correct?

Accepted Answer

Work is the product of force and displacement in the direction of the force: $$W = Fd \cos 	heta$$

Question 8

A 0.5 kg ball moving at 4 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\ \mathrm{m/s}$$

Question 9

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

Accepted Answer

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

Question 10

A 3 kg object moving at 2 m/s collides inelastically with a 2 kg object at rest. What is the final velocity of the combined mass?

Accepted Answer

$$v_f = \frac{m_1v_1 + m_2v_2}{m_1$ + m_2$} = \frac{3 	imes 2 + 2 	imes 0}{3 + 2} = 1.2\ \mathrm{m/s}$$

Question 11

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

$$T = \frac{mv^2$}{r} = \frac{0.2 	imes 3^2$}{0.5} = 3.6\ \mathrm{N}$$

Question 12

Which of the following is the correct expression for gravitational potential energy?

Accepted Answer

$$U = mgh$$

Question 13

A spring with spring constant $$k = 200\ \mathrm{N/m} is $$compressed by 0.1 m. What is the elastic potential energy stored in the spring?

Accepted Answer

$$U = \frac{1}{2}kx^2$ = \frac{1}{2} 	imes 200 	imes (0.1)^2$ = 1\ \mathrm{J}$$

Question 14

A projectile is launched at an angle $$	heta$$ with initial speed $$v_0. $$What is the maximum range on level ground?

Accepted Answer

$$R = \frac{v_0$^2 \sin 2	heta}{g}$$

Question 15

A 10 kg object is moving at 5 m/s. What is its kinetic energy?

Accepted Answer

$$KE = \frac{1}{2}mv^2$ = \frac{1}{2} 	imes 10 	imes 25 = 125\ \mathrm{J}$$

Question 16

A 0.5 kg mass attached to a spring oscillates with amplitude 0.2 m and frequency 2 Hz. What is its maximum speed?

Accepted Answer

$$v_{max} = 2\pi f A = 2 \pi 	imes 2 	imes 0.2 = 2.51\ \mathrm{m/s}$$

Question 17

A force of 50 N is applied to a lever arm of length 0.3 m at an angle of $$60^\circ to $$the arm. What is the torque produced?

Accepted Answer

$$	au = rF \sin 	heta = 0.3 	imes 50 	imes \sin 60^\circ = 12.99\ \mathrm{N \cdot m}$$

Question 18

A 1 kg object rotates in a circle of radius 2 m at a constant speed of 4 m/s. What is its angular momentum?

Accepted Answer

$$L = mvr = 1 	imes 4 	imes 2 = 8\ \mathrm{kg \cdot m^2$/s}$$

General Physics I – Course Syllabus and Schedule Overview

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