Q: A $$2\ \mathrm{kg}$$ block slides down a frictionless incline of height $$5\ \mathrm{m}. $$What is its speed at the bottom?

$$v = \sqrt{2gh} = \sqrt{2 \times 9.8 \times 5} \approx 9.9\ \mathrm{m/s}$$

Q: A $$5\ \mathrm{kg}$$ box is pulled across a horizontal surface with a force of $$20\ \mathrm{N}. If $$the coefficient of kinetic friction is $$0.2$$, what is the acceleration of the box?

$$a = \frac{F - f_k}{m} = \frac{20 - (0.2 \times 5 \times 9.8)}{5} \approx 1.84\ \mathrm{m/s^2$}$$

Q: A $$10\ \mathrm{kg}$$ object is dropped from a height of $$8\ \mathrm{m}. $$What is its velocity just before hitting the ground?

$$v = \sqrt{2gh} = \sqrt{2 \times 9.8 \times 8} \approx 12.5\ \mathrm{m/s}$$

Q: A $$0.2\ \mathrm{kg}$$ ball is attached to a $$0.5\ \mathrm{m}$$ string and swung in a horizontal circle at $$3\ \mathrm{m/s}. $$What is the tension in the string?

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

Question 1

A car accelerates uniformly from rest to a velocity of $$20\ \mathrm{m/s} in$$ $$5\ \mathrm{s}. $$What is the car's acceleration?

Accepted Answer

$$a = 4\ \mathrm{m/s^2$}$$

Question 2

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

Accepted Answer

The net force on an object is equal to the rate of change of its momentum.

Question 3

A $$2\ \mathrm{kg}$$ block slides down a frictionless incline of height $$5\ \mathrm{m}. $$What is its speed at the bottom?

Accepted Answer

$$v = \sqrt{2gh} = \sqrt{2 	imes 9.8 	imes 5} \approx 9.9\ \mathrm{m/s}$$

Question 4

A ball is thrown vertically upward with an initial velocity of $$15\ \mathrm{m/s}. $$Neglecting air resistance, how long does it take to reach its maximum height?

Accepted Answer

$$t = \frac{v_0$}{g} = \frac{15}{9.8} \approx 1.53\ \mathrm{s}$$

Question 5

Which of the following is a correct application of the conservation of momentum in a real-world scenario?

Accepted Answer

A gun recoils backward when it is fired because the momentum of the bullet is balanced by the momentum of the gun.

Question 6

A $$0.5\ \mathrm{kg}$$ ball moving at $$4\ \mathrm{m/s}$$ collides elastically with a stationary $$0.5\ \mathrm{kg}$$ ball. What is the velocity of the first ball after the collision?

Accepted Answer

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

Question 7

A $$3\ \mathrm{kg}$$ object is acted upon by a net force of $$12\ \mathrm{N}. $$What is its acceleration?

Accepted Answer

$$a = \frac{F}{m} = \frac{12}{3} = 4\ \mathrm{m/s^2$}$$

Question 8

Which graph best represents the motion of an object moving with constant acceleration?

Accepted Answer

A straight line with a nonzero slope on a velocity vs. time graph.

Question 9

A $$5\ \mathrm{kg}$$ box is pulled across a horizontal surface with a force of $$20\ \mathrm{N}. If $$the coefficient of kinetic friction is $$0.2$$, what is the acceleration of the box?

Accepted Answer

$$a = \frac{F - f_k}{m} = \frac{20 - (0.2 	imes 5 	imes 9.8)}{5} \approx 1.84\ \mathrm{m/s^2$}$$

Question 10

A pendulum of length $$1\ \mathrm{m}$$ swings with small amplitude. What is its period?

Accepted Answer

$$T = 2\pi \sqrt{\frac{l}{g}} = 2\pi \sqrt{\frac{1}{9.8}} \approx 2.01\ \mathrm{s}$$

Question 11

A $$10\ \mathrm{kg}$$ object is dropped from a height of $$8\ \mathrm{m}. $$What is its velocity just before hitting the ground?

Accepted Answer

$$v = \sqrt{2gh} = \sqrt{2 	imes 9.8 	imes 8} \approx 12.5\ \mathrm{m/s}$$

Question 12

A $$0.2\ \mathrm{kg}$$ ball is attached to a $$0.5\ \mathrm{m}$$ string and swung in a horizontal circle at $$3\ \mathrm{m/s}. $$What is the tension in the string?

Accepted Answer

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

Question 13

Which of the following statements about periodic motion is correct?

Accepted Answer

The period is the time required for one complete cycle of motion.

Question 14

A $$1\ \mathrm{kg}$$ mass is attached to a spring with spring constant $$k = 100\ \mathrm{N/m}. $$What is the period of oscillation?

Accepted Answer

$$T = 2\pi \sqrt{\frac{m}{k}} = 2\pi \sqrt{\frac{1}{100}} \approx 0.63\ \mathrm{s}$$

Question 15

A $$0.3\ \mathrm{kg}$$ cart moving at $$2\ \mathrm{m/s}$$ collides inelastically with a $$0.2\ \mathrm{kg}$$ cart at rest. What is their final velocity?

Accepted Answer

$$v_f = \frac{m_1v_1 + m_2v_2}{m_1$ + m_2$} = \frac{0.3 	imes 2 + 0.2 	imes 0}{0.3 + 0.2} = 1.2\ \mathrm{m/s}$$

Question 16

Which of the following is a correct statement about the scientific method in physics?

Accepted Answer

It involves making observations, forming hypotheses, conducting experiments, and analyzing results.

Question 17

A $$0.4\ \mathrm{kg}$$ object moves in a circle of radius $$0.6\ \mathrm{m} at$$ $$2\ \mathrm{m/s}. $$What is its centripetal acceleration?

Accepted Answer

$$a_c = \frac{v^2$}{r} = \frac{4}{0.6} \approx 6.67\ \mathrm{m/s^2$}$$

Question 18

A $$2\ \mathrm{kg}$$ block is at rest on a frictionless surface. A $$6\ \mathrm{N}$$ force acts on it for $$3\ \mathrm{s}. $$What is its final velocity?

Accepted Answer

$$v = at = \frac{F}{m}t = \frac{6}{2} 	imes 3 = 9\ \mathrm{m/s}$$

Question 19

Which of the following is NOT a valid use of a free-body diagram?

Accepted Answer

To show the trajectory of an object over time.

PHY 2048 Physics with Calculus I – Syllabus and Course Overview

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