Question 1

A car moves along a straight road with a position given by $$x(t) = 5 + 4t + 3t^2$. What is the car's instantaneous acceleration?

Accepted Answer

$$a(t) = 6$$

Question 2

Which of the following best describes the physical meaning of the slope of a position vs. time ($$x$$-$$t) $$graph at a given instant?

Accepted Answer

It represents the object's instantaneous velocity.

Question 3

A turtle and a rabbit are racing over a distance of 1500 m. The turtle's average speed is $$0.9\ \mathrm{m/s}$$ and the rabbit's is $$9\ \mathrm{m/s}. $$What is the maximum time (in minutes) the rabbit can wait before starting and still win?

Accepted Answer

22 minutes

Question 4

Which equation gives the position $$x of an $$object at time $$t if it $$starts at $$x_0$$ with initial velocity $$v_0$$ and moves with constant acceleration $$a$$?

Accepted Answer

$$x = x_0$ + v_0$ t + \frac{1}{2} a t^2$

Question 5

A small block slides down a frictionless incline with constant acceleration. It is released from rest at the top. After traveling $$6.80\ \mathrm{m}$$, its speed is $$3.80\ \mathrm{m/s}. $$What is its speed after traveling $$3.40\ \mathrm{m}$$?

Accepted Answer

$$2.69\ \mathrm{m/s}$$

Question 6

Which of the following is the correct formula for velocity as a function of time for motion with constant acceleration?

Accepted Answer

$$v = v_0$ + a t$$

Question 7

A rock is thrown straight up from a bridge and passes you on its way down 6.00 s later. If the rock falls 28.0 m below the point where it was released, what is its speed just before hitting the water? (Ignore air resistance, $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$v = 37.6\ \mathrm{m/s}$$

Question 8

If the positive direction is chosen upwards, what is the acceleration $$a$$ for a freely falling body near Earth's surface?

Accepted Answer

$$a = -g$$

Question 9

An antelope moving with constant acceleration covers $$70.0\ \mathrm{m} in$$ $$7.00\ \mathrm{s}$$, reaching a speed of $$15.0\ \mathrm{m/s} at $$the end. What was its speed at the start?

Accepted Answer

$$10.0\ \mathrm{m/s}$$

Question 10

Which of the following equations is most useful for finding the final velocity of an object when time is not given, but displacement and acceleration are known?

Accepted Answer

$$v^2$$ = $$v_0^2 + 2 a x$

Question 11

A police car traveling at $$95\ \mathrm{km/h} is $$passed by a speeder at $$135\ \mathrm{km/h}. $$One second later, the police accelerates at $$2.60\ \mathrm{m/s^2$}. $$How much time passes before the police overtakes the speeder (assuming the speeder moves at constant speed)?

Accepted Answer

23.7 s

Question 12

The area under a velocity vs. time ($$v$$-$$t) $$graph between $$t_0$$ and $$t_1$$ represents:

Accepted Answer

The object's displacement

Question 13

An automobile traveling $$95\ \mathrm{km/h}$$ overtakes a $$1.50\ \mathrm{km}$$ long train traveling at $$75\ \mathrm{km/h}. $$How long does it take the car to pass the train?

Accepted Answer

270 s

Question 14

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

Accepted Answer

$$v = \frac{dx}{dt}$$

Question 15

If the acceleration of an object is zero, which of the following statements is true?

Accepted Answer

The velocity is constant.

Question 16

A solar-powered car accelerates from rest to $$60\ \mathrm{km/h} in$$ $$20\ \mathrm{s}$$, cruises for $$20\ \mathrm{s}$$, then brakes to a stop in $$40\ \mathrm{s}. $$What is the average acceleration during the first $$20\ \mathrm{s}$$?

Accepted Answer

$$0.83\ \mathrm{m/s^2$}$$

Question 17

Which of the following is true about the direction of acceleration for a freely falling body near Earth's surface?

Accepted Answer

It is always downwards.

Question 18

The change in velocity of an object is represented by the area under which graph?

Accepted Answer

Acceleration vs. time ($$a$$-$$t) $$graph

Question 19

Which of the following is NOT a possible case for instantaneous velocity?

Accepted Answer

Always equal to zero

Kinematics in One Dimension: Motion Along a Straight Line

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