Question 1

A car travels in a straight line with a constant velocity of $$20 \ \mathrm{m/s}$$ for $$10 \ \mathrm{s}. $$What is the displacement of the car during this time?

Accepted Answer

$$200 \ \mathrm{m}$$

Question 2

Which of the following statements best distinguishes between mass and weight?

Accepted Answer

Mass is a measure of the amount of matter in an object, while weight is the force exerted on that mass by gravity.

Question 3

A ball is thrown horizontally from the top of a $$45 \ \mathrm{m}$$ high cliff with a speed of $$10 \ \mathrm{m/s}. $$How long does it take to hit the ground? (Ignore air resistance, $$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$3.03 \ \mathrm{s}$$

Question 4

Which of the following is the correct expression for the acceleration of an object moving in a circle of radius $$R at $$constant speed $$v$$?

Accepted Answer

$$a = \frac{v^2$}{R}$$

Question 5

A block of mass $$2 \ \mathrm{kg} is $$pulled across a horizontal surface with a constant force of $$10 \ \mathrm{N}. If $$the coefficient of kinetic friction is $$0.2$$, what is the acceleration of the block? ($$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$3.04 \ \mathrm{m/s^2$}$$

Question 6

Which of the following best describes the difference between static and kinetic friction?

Accepted Answer

Static friction prevents motion up to a maximum value, while kinetic friction acts when objects are sliding past each other.

Question 7

A projectile is launched at an angle of $$30^\circ$$ above the horizontal with an initial speed of $$40 \ \mathrm{m/s}. $$What is the initial vertical component of its velocity?

Accepted Answer

$$40 \sin 30^\circ = 20 \ \mathrm{m/s}$$

Question 8

A $$5 \ \mathrm{kg}$$ object is moving in a circle of radius $$2 \ \mathrm{m} at a $$constant speed of $$4 \ \mathrm{m/s}. $$What is the magnitude of the net force acting on the object?

Accepted Answer

$$20 \ \mathrm{N}$$

Question 9

Which of the following is NOT a vector quantity?

Accepted Answer

Speed

Question 10

A car accelerates uniformly from rest to $$30 \ \mathrm{m/s} in$$ $$10 \ \mathrm{s}. $$What is the acceleration?

Accepted Answer

$$2.0 \ \mathrm{m/s^2$}$$

Question 11

A $$10 \ \mathrm{kg}$$ box is suspended by a rope. What is the tension in the rope if the box is at rest? ($$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$98 \ \mathrm{N}$$

Question 12

A graph of velocity vs. time for an object moving in a straight line is a straight line with a positive slope. What does the slope of this graph represent?

Accepted Answer

Acceleration

Question 13

A $$0.5 \ \mathrm{kg}$$ ball is dropped from rest from a height of $$20 \ \mathrm{m}. $$What is its speed just before hitting the ground? (Ignore air resistance, $$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$14.0 \ \mathrm{m/s}$$

Question 14

A $$3 \ \mathrm{kg}$$ object is acted on by two forces: $$5 \ \mathrm{N} to $$the right and $$2 \ \mathrm{N} to $$the left. What is the acceleration of the object?

Accepted Answer

$$1 \ \mathrm{m/s^2$} to $$the right

Question 15

A cyclist moves with a constant speed of $$12 \ \mathrm{m/s}$$ around a circular track of radius $$30 \ \mathrm{m}. $$What is the magnitude of the centripetal acceleration?

Accepted Answer

$$4.8 \ \mathrm{m/s^2$}$$

Question 16

A $$1 \ \mathrm{kg}$$ object is moving in a circle of radius $$0.5 \ \mathrm{m} at a $$speed of $$2 \ \mathrm{m/s}. $$What is the required centripetal force?

Accepted Answer

$$8 \ \mathrm{N}$$

Physics 7A Midterm Exam Study Guide: Motion, Newton's Laws, and Forces

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