Q: A car accelerates from rest at $$2\ \mathrm{m/s^2$}$$ for $$5$$ seconds. What is its final velocity?

$$v = v_0$ + a t = 0 + 2 \times 5 = 10\ \mathrm{m/s}$$

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

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

Question 1

Which of the following best describes the scientific method as applied in physics?

Accepted Answer

A systematic approach involving observation, hypothesis, experimentation, and analysis.

Question 2

A car travels 60 km north, then 80 km east. What is the magnitude of its displacement?

Accepted Answer

$$\sqrt{60^2$ + 80^2$} = 100 km$$

Question 3

Which of the following is a vector quantity?

Accepted Answer

Displacement

Question 4

A ball is thrown straight up with an initial velocity of $$10\ \mathrm{m/s}. $$What is its velocity after $$1$$ second? (Assume $$g = 9.8\ \mathrm{m/s^2$}$$ downward)

Accepted Answer

$$10 - 9.8 = 0.2\ \mathrm{m/s}$$

Question 5

Which equation correctly relates acceleration ($$a$$), initial velocity ($$v_0$$), time ($$t$$), and displacement ($$x) $$for constant acceleration?

Accepted Answer

$$x = v_0$ t + \frac{1}{2} a t^2$

Question 6

A projectile is launched at an angle of $$30^\circ$$ with an initial speed of $$20\ \mathrm{m/s}. $$What is the initial vertical component of its velocity?

Accepted Answer

$$20 \sin 30^\circ = 10\ \mathrm{m/s}$$

Question 7

Which of the following statements about Newton's First Law is correct?

Accepted Answer

An object at rest will remain at rest unless acted upon by a net force.

Question 8

A $$5\ \mathrm{kg}$$ box is pulled with a force of $$20\ \mathrm{N} on a $$frictionless surface. What is its acceleration?

Accepted Answer

$$a = \frac{F}{m} = \frac{20}{5} = 4\ \mathrm{m/s^2$}$$

Question 9

Which of the following is NOT a fundamental SI unit?

Accepted Answer

Newton

Question 10

A car accelerates from rest at $$2\ \mathrm{m/s^2$}$$ for $$5$$ seconds. What is its final velocity?

Accepted Answer

$$v = v_0$ + a t = 0 + 2 	imes 5 = 10\ \mathrm{m/s}$$

Question 11

Which of the following best describes the difference between mass and weight?

Accepted Answer

Mass is the amount of matter in an object; weight is the force due to gravity acting on that mass.

Question 12

A $$10\ \mathrm{kg}$$ object is dropped from a height of $$5\ \mathrm{m}. $$What is its speed just before hitting the ground? (Ignore air resistance, $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

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

Question 13

Which of the following is a correct statement of Newton's Third Law?

Accepted Answer

For every action, there is an equal and opposite reaction.

Question 14

A $$2\ \mathrm{kg}$$ object moves in a circle of radius $$3\ \mathrm{m} at a $$constant speed of $$4\ \mathrm{m/s}. $$What is the magnitude of the centripetal force?

Accepted Answer

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

Question 15

Which of the following is a scalar quantity?

Accepted Answer

Speed

Question 16

A runner completes a $$400\ \mathrm{m}$$ lap in $$50$$ seconds. What is their average speed?

Accepted Answer

$$\frac{400}{50} = 8\ \mathrm{m/s}$$

Question 17

A $$3\ \mathrm{kg}$$ object is acted on by two forces: $$5\ \mathrm{N}$$ east and $$12\ \mathrm{N}$$ north. What is the magnitude of the net force?

Accepted Answer

$$\sqrt{5^2$ + 12^2$} = 13\ \mathrm{N}$$

Question 18

Which of the following best describes the concept of inertia?

Accepted Answer

The tendency of an object to resist changes in its state of motion.

Question 19

A $$1\ \mathrm{kg}$$ object is dropped from rest and falls for $$3$$ seconds. What is its velocity just before hitting the ground? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$v = g t = 9.8 	imes 3 = 29.4\ \mathrm{m/s}$$

Physics Midterm Study Guide: Key Concepts and Topics

스터디 가이드 - 연습 문제

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