Question 1

A car is moving eastward and slowing down. What is the direction of its acceleration vector?

Accepted Answer

Westward

Question 2

Which of the following statements about free fall near the surface of Earth is correct?

Accepted Answer

All objects fall with an identical rate of acceleration, $$g = 9.8\,\mathrm{m/s^2$}$$, neglecting air resistance.

Question 3

You throw your keys straight up in the air. At the highest point in the key’s path, which of the following is true?

Accepted Answer

Acceleration is non-zero, but velocity is zero.

Question 4

A hammer and a feather are dropped from the same height on the Moon. Which one hits the ground first?

Accepted Answer

They hit at the same time

Question 5

A student throws a stone vertically downward from a bridge with an initial speed of $$14.7\,\mathrm{m/s}. If $$the stone hits the water $$2.00\,\mathrm{s}$$ later, what is the height of the bridge above the water? (Take $$g = 9.8\,\mathrm{m/s^2$}$$ downward.)

Accepted Answer

$$49\,\mathrm{m}$$

Question 6

A projectile is launched from ground level with an initial speed of $$220\,\mathrm{m/s} at an $$angle of $$45^ $$ above the horizontal. What is the maximum height reached by the projectile? (Use $$g = 9.8\,\mathrm{m/s^2$}.)$$

Accepted Answer

$$1230\,\mathrm{m}$$

Question 7

A football is kicked with an upward vertical component of $$14\,\mathrm{m/s}$$ and a horizontal component of $$12\,\mathrm{m/s}. $$When the ball reaches its maximum height, what is its speed? (Neglect air resistance.)

Accepted Answer

$$12\,\mathrm{m/s}$$

Question 8

Which of the following is NOT necessarily consistent with a car that is accelerating?

Accepted Answer

A car is moving with a high speed.

Question 9

A vector $$\vec{A}$$ has a magnitude $$A$$ and makes an angle $$	heta$$ with the y-axis. What is the length of the projection of $$\vec{A}$$ onto the y-axis?

Accepted Answer

$$A \sin 	heta$$

Question 10

A squirrel starts at the base of a flagpole that is $$3.0\,\mathrm{m}$$ east of the house and $$5.0\,\mathrm{m}$$ north of the fence. It ends up at a bird feeder $$4.0\,\mathrm{m}$$ east of the house and $$2.0\,\mathrm{m}$$ north of the fence. What is the displacement vector of the squirrel?

Accepted Answer

$$\Delta x = 1.0\,\mathrm{m}$$, $$\Delta y = -3.0\,\mathrm{m}$$

Question 11

A ball is thrown horizontally from a balcony $$22\,\mathrm{m}$$ above the ground with a speed of $$12\,\mathrm{m/s}. $$How long does it take to hit the ground? (Neglect air resistance, $$g = 9.8\,\mathrm{m/s^2$}.)$$

Accepted Answer

$$2.1\,\mathrm{s}$$

Question 12

A ball is thrown horizontally from a balcony $$22\,\mathrm{m}$$ above the ground with a speed of $$12\,\mathrm{m/s}. $$How far from the base of the balcony does it land? (Neglect air resistance, $$g = 9.8\,\mathrm{m/s^2$}.)$$

Accepted Answer

$$25\,\mathrm{m}$$

Question 13

Which of the following statements about projectile motion is correct (neglecting air resistance)?

Accepted Answer

The horizontal velocity is constant.

Question 14

A horse travels at constant speed around a circular track, taking $$20.0\,\mathrm{s} to $$complete one revolution. The circumference of the track is $$31.4\,\mathrm{m}. $$What is the magnitude of the horse’s velocity?

Accepted Answer

$$1.57\,\mathrm{m/s}$$

Question 15

In uniform circular motion, what is the direction of the centripetal acceleration?

Accepted Answer

Toward the center of the circle

Question 16

A rock is thrown from the top of a castle wall with an initial velocity of $$12\,\mathrm{m/s} at$$ $$42^ $$ above the horizontal. It lands $$9.5\,\mathrm{m}$$ below the initial height. What is the magnitude of its velocity just before landing? (Take $$g = 9.8\,\mathrm{m/s^2$}.)$$

Accepted Answer

$$18.1\,\mathrm{m/s}$$

Question 17

Which of the following is true about the magnitude of a vector?

Accepted Answer

It is always positive.

Question 18

If a vector $$\vec{A}$$ has components $$A_x$$ and $$A_y$$, what is its magnitude?

Accepted Answer

$$\sqrt{A_x^2$ + A_y^2$}$$

Kinematics and Acceleration: Study Notes for Introductory Physics

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