Question 1

A car moves along a straight road such that its position as a function of time is given by $$x(t) = 4.0\,\mathrm{m} + (2.0\,\mathrm{m/s})t + (1.0\,\mathrm{m/s^2$})t^2$. What is the car's instantaneous velocity at t = 3.0$$\,\mathrm{s}$$?

Accepted Answer

$$v_x = 8.0\,\mathrm{m/s}$$

Question 2

A runner completes a 100 m dash in 10 s, starting from rest and accelerating uniformly. What is the runner's average velocity during the dash?

Accepted Answer

$$10\,\mathrm{m/s}$$

Question 3

A ball is thrown vertically upward from the ground with an initial velocity of $$20\,\mathrm{m/s}. $$Neglecting air resistance, what is the maximum height reached by the ball? (Take $$g = 9.8\,\mathrm{m/s^2$}$$ downward.)

Accepted Answer

$$20.4\,\mathrm{m}$$

Question 4

Which of the following statements about velocity and speed is correct?

Accepted Answer

Average speed is not necessarily equal to the magnitude of average velocity.

Question 5

A cheetah's position is given by $$x = 20\,\mathrm{m} + (5.0\,\mathrm{m/s^2$})t^2$. What is the cheetah's instantaneous velocity at t = 2.0$$\,\mathrm{s}$$?

Accepted Answer

$$v_x = 20.0\,\mathrm{m/s}$$

Question 6

A car accelerates from rest at $$3.0\,\mathrm{m/s^2$}$$ for $$5.0\,\mathrm{s}. $$What is its final velocity?

Accepted Answer

$$v_x = 15.0\,\mathrm{m/s}$$

Question 7

A stone is dropped from rest from a cliff and falls freely under gravity. How far does it fall in the first 3 seconds? (Take $$g = 9.8\,\mathrm{m/s^2$}$$ downward.)

Accepted Answer

$$44.1\,\mathrm{m}$$

Question 8

A motorcyclist moves east at $$15\,\mathrm{m/s}$$ and accelerates at $$4.0\,\mathrm{m/s^2$}$$ for $$2.0\,\mathrm{s}. $$What is his velocity at the end of this interval?

Accepted Answer

$$v_x = 23.0\,\mathrm{m/s}$$

Question 9

A police officer starts from rest and accelerates at $$3.0\,\mathrm{m/s^2$} in $$pursuit of a car moving at $$15\,\mathrm{m/s}. $$How long does it take for the officer to catch up with the car?

Accepted Answer

$$15\,\mathrm{s}$$

Question 10

Which of the following is the correct equation for the position $$x of a $$particle moving with constant acceleration $$a_x$$?

Accepted Answer

$$x = x_0$ + v$$_{0x}$$t + \frac{1}{2}a_xt^2$

Question 11

A ball is thrown straight up with an initial velocity of $$12\,\mathrm{m/s}. $$How long does it take to reach its maximum height? (Take $$g = 9.8\,\mathrm{m/s^2$}$$ downward.)

Accepted Answer

$$1.22\,\mathrm{s}$$

Question 12

Which of the following best describes the acceleration of a freely falling object near Earth's surface (neglecting air resistance)?

Accepted Answer

It is constant and directed downward.

Question 13

A car's velocity changes from $$10\,\mathrm{m/s} to$$ $$30\,\mathrm{m/s} in$$ $$5.0\,\mathrm{s}. $$What is its average acceleration?

Accepted Answer

$$4.0\,\mathrm{m/s^2$}$$

Question 14

A position-time graph for a moving object is a straight line with a positive slope. What does this indicate about the object's motion?

Accepted Answer

The object moves with constant positive velocity.

Question 15

A ball is thrown downward from a building with an initial velocity of $$5.0\,\mathrm{m/s}. $$How fast is it moving after $$2.0\,\mathrm{s}$$? (Take $$g = 9.8\,\mathrm{m/s^2$}$$ downward.)

Accepted Answer

$$24.6\,\mathrm{m/s}$$

Question 16

Which of the following is the correct expression for instantaneous acceleration?

Accepted Answer

$$a_x = \frac{dv_x}{dt}$$

Question 17

A car travels 60 km east in 1 hour, then 60 km west in 1 hour. What is the car's average velocity for the entire trip?

Accepted Answer

$$0\,\mathrm{km/h}$$

Question 18

A particle moves along the x-axis with velocity $$v_x = 6.0\,\mathrm{m/s} - (2.0\,\mathrm{m/s^2$})t. At $$what time does the particle come to rest?

Accepted Answer

$$t = 3.0\,\mathrm{s}$$

Motion Along a Straight Line: Kinematics in One Dimension

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