# Concepts, 1D Kinematics

Source: UC Boulder PhET

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This pack is intended for incoming freshman physics students: it covers basic concepts such as scientific notation and units, along with introductory notions of 1D motion.

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[Concepts, 1D Kinematics] 1

[Mazur] An object goes from one point in space to another. After it arrives at its destination, the size of its displacement is ___ than the distance it traveled.

A

either greater than or equal to

B

always equal to

C

either smaller than or equal to

D

could be smaller or larger

[Concepts, 1D Kinematics] 2

[UColorado] Steve is pacing back and forth in lecture. He starts at x =+10 (measured in dm from the edge of the bench), moves right to x=+30, moves back left to +20, then finally moves right to +50, as shown. What is the distance travelled, and the displacement?

A

Distance = +40, displacement = +40 (dm)

B

Distance = +60, displacement = +40 (dm)

C

Distance = +40, displacement = +60 (dm)

D

Distance = +60, displacement = +60 (dm)

[Concepts, 1D Kinematics] 3

[UColorado] An ant crawling along the floor follows a semi-circular path, going half way around the circumference of a circle of radius R.

The distance travelled, and the displacement of the ant, are respectively:

A

Distance = $\pi R$, displacement = $\pi R$

B

Distance = $2R$, displacement = $\pi R$

C

Distance = $\pi R$, displacement = $2R$

D

Distance = $\pi R$, displacement = $0$

E

None of these

[Concepts, 1D Kinematics] 4

[UColorado] A race car (shown as a dot) is moving as shown in the one dimensional motion diagram. Throughout the period of time shown, what are the signs of position, x, and velocity, v?

A

x:-, v: -

B

x:-, v:+

C

x:+, v:-

D

x:+, v:+

E

None of these/Not sure

[Concepts, 1D Kinematics] 5

[UColorado] A race car (shown as a dot) is moving as shown in the one dimensional motion diagram. Throughout the period of time shown, what is the sign of acceleration, a?

A

+

B

-

C

Not enough information/not sure

[Concepts, 1D Kinematics] 6

[UColorado] A person starts in Boulder, drives to Denver (50 km away) in 1 hour, stays in Denver 1 hour, then speeds back to Boulder in 30 minutes. What is the average speed of the round trip?

A

25 km/hr

B

67 km/hr

C

40 km/hr

D

75 km/hr

E

none of these

[Concepts, 1D Kinematics] 7

[UColorado] A marathon runner runs at a steady 15 km/hr. When the runner is 7.5 km from the finish, a bird begins flying from the runner to the finish at 30 km/hr. When the bird reaches the finish line, it turns around and flies back to the runner, and then turns around again, repeating the back-and-forth trips until the runner reaches the finish line. How many kilometers does the bird travel?

A

10 km

B

15 km

C

20 km

D

Not sure/ impossible to decide

[Concepts, 1D Kinematics] 8

[Mazur] A person initially at point 3 on the x-axis stays there for a while and then strolls along the x-axis to point 1, stays there for a bit and then runs to point 2 and remains there. Which of the following graphs depicts this motion?

A

a

B

b

C

c

D

d

E

None of the above

[Concepts, 1D Kinematics] 9

[UColorado] The "multiflash photograph" below shows a ball rolling along a surface. The camera flashed once a second, and the time is shown above each image. Which graph best represents the ball's motion?

A

a

B

b

C

c

D

d

E

none of these is remotely correct.

[Concepts, 1D Kinematics] 10

[UColorado] Order the speeds at times 1, 2, and 3 from the slowest to the fastest.

A

$s_1 < s_2 < s_3$

B

$s_2 < s_1 < s_3$

C

$s_3 < s_1 < s_2$

D

$s_3 < s_2 < s_1$

E

None of these/not sure

[Concepts, 1D Kinematics] 11

[UColorado] A train moves along a straight track and a graph of its position vs time looks like the top graph. Which of the graphs below depicts the train's velocity as a function of time?

A

a

B

b

C

c

D

d

E

None of these

[Concepts, 1D Kinematics] 12

[UColorado] A train moves along a straight track and its position vs. time is shown in the top graph.

Which graph best depicts the train's velocity vs. time?

A

a

B

b

C

c

D

d

E

None

[Concepts, 1D Kinematics] 13

[UColorado] Which object, A or B, has the higher speed?

A

a

B

b

[Concepts, 1D Kinematics] 14

[UColorado] A particle starts at the origin. Below is a graph of velocity vs. time. What is the approximate position at t=3 sec?

A

3m

B

6m

C

9m

D

18m

E

None of these/not enough information.

[Concepts, 1D Kinematics] 15

[Mazur] A train car moves along a long straight track. The graph shows the position as a function of time for this train. The graph shows that the train:

A

speeds up all the time.

B

slows down all the time.

C

speeds up part of the time and slows down pa

D

moves at a constant velocity.

[Concepts, 1D Kinematics] 16

[Mazur] The graph shows position as a function of time for two trains running on parallel tracks. Which is true:

A

At time $t_B$, both trains have the same velocity.

B

Both trains speed up all the time.

C

Both trains have the same velocity at some time before $t_B$.

D

Somewhere on the graph, both trains have the same acceleration.

[Concepts, 1D Kinematics] 17

[UColorado] A train moves along a straight track and a graph of its position vs time is shown in the top graph. Which of the graphs below depicts the train's acceleration as a function of time?

A

a

B

b

C

c

D

d

E

None of these

[Concepts, 1D Kinematics] 18

[UColorado] A truck traveling at 50 km/hr (about 14 m/s) approaches a car stopped at a red light. When the truck is 100 m from the car, the light turns green and the car immediately begins to accelerate at 2 m/s2 to a final speed of 100 km/hr. Which graph represents this situation?

A

a

B

b

C

c

D

None of these

[Concepts, 1D Kinematics] 19

[UColorado] I drop a book at t=0. Which plot below best represents position as a function of time?

A

a

B

b

C

c

D

d

[Concepts, 1D Kinematics] 20

[UColorado] I drop a book at t=0. Which plot below best represents velocity as a function of time?

A

a

B

b

C

c

D

d

[Concepts, 1D Kinematics] 21

[UColorado] An elevator is going up at a constant speed. Near the top floor, it starts to slow to a stop. During the period that it is slowing down, its acceleration is:

A

downward.

B

upward.

C

in some other direction.

[Concepts, 1D Kinematics] 22

[UColorado] A ball is thrown straight upward. At the top of its trajectory, its acceleration is..

A

zero

B

straight up

C

straight down

D

depends on the mass of the ball

[Concepts, 1D Kinematics] 23

[UColorado] A ball is fired straight downward out of a special spring-loaded gun, which produces constant acceleration. Upward is chosen as the positive direction. Assume that air resistance is negligible. Which graph properly represents acceleration of the ball?

A

a

B

b

C

c

D

d

[Concepts, 1D Kinematics] 24

[Mazur] A person standing at the edge of a cliff throws one ball straight up and another ball straight down at the same initial speed. Neglecting air resistance, which ball has the greater speed when it hits the ground?

A

The ball thrown upward.

B

The ball thrown downward.

C

Neither—they both hit at the same speed.

[Concepts, 1D Kinematics] 25

[Mazur] If you drop an object in the absence of air resistance, it accelerates downward at $9.8 m/s^2$. If instead you throw it downward, its downward acceleration after release is

A

less than $9.8 m/s^2$

B

$9.8 m/s^2$

C

$more than 9.8 m/s^2$

[Concepts, 1D Kinematics] 26

[Mazur] A ball is thrown straight up. At the top of its trajectory, its

A

velocity is zero, acceleration is zero

B

velocity is non-zero, acceleration is non-zero.

C

velocity is zero, acceleration is non-zero.

D

velocity is non-zero, acceleration is zero.

[Concepts, 1D Kinematics] 27

[UColorado] On Planet X, a rock is thrown straight up. The position and velocity of the ball at various times are listed in the table. (Note: "up" is chosen as the "+" direction.) What is the acceleration due to gravity on Planet X?

A

-5 $m/s^2$

B

-10 $m/s^2$

C

-15 $m/s^2$

D

-20 $m/s^2$

E

None of these

[Concepts, 1D Kinematics] 28

[UColorado] A ball is launched straight up with some initial velocity. (Neglect air resistance.) If the initial velocity is doubled, the time to reach the apex of the trajectory...

A

doubles.

B

increases by a factor of 4.

C

Neither of these.

D

Not enough information given.

[Concepts, 1D Kinematics] 29

[UColorado] A ball is launched straight up with some initial velocity. (Neglect air resistance.) If the initial velocity is doubled, the maximum height of the ball...

A

doubles.

B

increases by a factor of 4.

C

Neither of these.

D

Not enough information given.

[Concepts, 1D Kinematics] 30

[UColorado] A helicopter takes off vertically, with a constant speed $v_0$. While rising, the pilot releases a cigarette butt. (Neglect air resistance!) The cigarette will...

A

Initially rise with speed $v_0$, reduce its speed, come to rest, and then increase its speed as it goes down.

B

Not go up at all, but will start to gain downwards speed as it drops to the ground.

C

Drop to the ground with a constant speed.

[Concepts, 1D Kinematics] 31

[UColorado] A square with edge length L is made larger and larger.

As the square grows, the ratio $\frac{length-of-perimeter}{area}$...

A

increases

B

decreases

C

remains constant

D

I have no idea

[Concepts, 1D Kinematics] 32

[UColorado] One meter is 100 $cm$. If you have a hot tub with a volume of 1 cubic meter $(1 m^3)$, how many cubic centimeters is that?

A

100cm^3

B

1,000cm^3

C

1,000,000cm^3

D

1,000,000,000cm^3

E

None of these/not sure

[Concepts, 1D Kinematics] 33

$10^5=?$

A

1E5

B

10E5

C

something else

D

No idea

[Concepts, 1D Kinematics] 34

[UColorado] As I walk, what is my typical speed?

A

0.2 m/s

B

2.0 m/s

C

20 m/s

D

Impossible - I need a calculator...