# UNIT 2 KINEMATICS REVIEW

Mechanics

Nov 14, 2013 (4 years and 5 months ago)

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Physics

2012

Name: _________________

UNIT 2

KINEMATICS REVIEW

Date: _______ Period:_____

1)

When you look at the speedometer in a moving car, you can see the car’s _____.

(A) instantaneous speed.

(B) average speed

(C) average acceleration

(D
) instantaneous acceleration

(E) average distance traveled

(F) instantaneous positi
on

2
)

A boat is traveling west with a constant velocity
of 33

m/s. Which of the following statements is true?

(A) The boat has a positive acceleration.

(B) The boat has a negative acceleration.

(C) The boat has zero
acceleration.

(D) The boat is not moving.

3
)

If a swimmer has to swim 5 laps of the pool (to the end and back), with one length of the pool being 50

meters,
what is the swimmer’s
distance and
displacement?

(A) 250m
, 250 m

(B) 500m
, 500m

(C)
500 m, 0m

(D) 500 m, 250m

4
)

A wallaby
, travelling north, has

a positive initial velocity and a negative acceleration
. Which of the following
best
describes

the motion of the wallaby?

(A) The wallaby has a constant speed.

(B)

The wallaby is speeding up.

(C) The wallaby is slowing down.

(D) The wallaby is travelling in a negative direction.

True or F
alse:

5
)

The rate at which distance is covered is called speed.
___
True
________

6
)

Average speed is defi
ned as the time it takes for a
trip divided by
the distance

travel
ed
.

_____
True
______

7
)

Velocity is different from speed in that velocity is speed
in a
given direction.

____
True
_______

8
)

The SI unit of velocity is the meter.

__
False m/s
_________

9
)

The SI unit of acceleration is m/s.

___
False m/
s
2
________

10)

The rate at which velocity changes with time is called acceleration. _____
True
______

11
)

When a car rounds a corner at constant speed, its acceleration is zero.

___
False (constant direction)
____
_

12
)

Even though a car is slowing
down, it
is still accelerating.

__
True
_________

13
)

Complete the following Units Table

Name of
Physical Quantity

Symbol

SI Unit

Time

t

s

Acceleration

a

m/s
2

Speed

v

m/s

Velocity

v

m/s

Displacement

Δd

m

Distance

d

m

Problems
:

Complete
using the required
GUESS method
!

14)

If the
average speed of a cheetah

is

21.7 m/s, how far can it run
in 3.0 seconds?

Diagram: (Given + Unknowns)

v = 21.7 m/s

Δd = ????? m

t = 3.0 s

Equation:

v
ave
=
Δd

t

Substitute:

21.7

=
Δd

Cross multiply

Δd = (21.7)(3.0)

3

Solve:

Δd
= 65.1 m

15
)

Starting from rest, a car undergoes a constant acceleration of 6.0 m/s
2
. How far will the car travel in the first
second of
travel?

Diagram: (Given + Unknowns)

a = 6 m/s
2

v
f

=

v
i

= 0 m/s

t = 1 s

Δd = ??? m

Equation
:

∆ d = (v
i
)t + (1/2) a (t)
2

Substitute:

∆ d = (0)(1) + (1/2)(6)(1)
2

Solve:

Δd = 3.0 m

16
)

How far does a car travel

with an acceleration of 4.0 m/s
2

take to go from 10 m/s to 30 m/s?

Diagram: (Given + Unknowns)

a = 4 m/s
2

v
f

= 30 m/s

v
i

= 10 m/s

t =

Δd = ??? m

Equation:

a =
(v
f
2

v
i
2
)

2Δd
=
S畢st楴u瑥:
=
4 =
(30
2

10
2
)

Switch the 4 and

Δd

Δd =
(30
2

10
2
)

2Δd
2(4)

Δd =
800

8

Solve:

Δd = 100 m
=
=

)=A⁳瑯te⁩=⁤ropped⁦=om⁡⁣l楦映w楴h
=
no⁩n楴楡l=veloc楴礮y⁔he=s瑯te⁨as=a⁶er瑩cal⁡ccelera瑩on⁯映f.8⁭/s
2
. After
it has fallen 128.6 m, what is the stone’s final velocity?

Diagram: (Given + Unknowns)

a = 9.8 m/s
2

v
f

= ??? m/s

v
i

= 0 m/s

t =

Δd = 128.6 m

Equation:

a =
(v
f
2

v
i
2
)

2Δd
=
Substitute:

9.8 =
(v
f
2

0
2
)

Cross Mult

2520.56

= v
f
2

2(128.6)

Take the square root : v
f

= 50.2 m/s

Solve:

v
f

= 50.2 m/s

18
)

In the story of the tortoise and
hare, a hare traveling 0.75 m/s accelerates uniformly for 3 second to pass
the tortoise. The hare travels 38.25 m during the 3 second interval that it was accelerating. What is the hare’s
speed at the end of the acceleration period?

Diagram: (Given +
Un
knowns)

a =

v
f

= ??? m/s

v
i

= 0.75 m/s

t = 3 s

Δd 38.25 m

Hint:
Find a first
then find v
f

Equation:

∆ d = (v
i
)t
+
(1/2) a (t)
2
a =
(v
f

v
i
)

t

Sub:
38.25
=
(0
.75)(3) +
(1/2)(a)(3)
2

38.25 = 2.25+
4.5a subtract 2.25

36

= 4.5a divide

8 m/s
2

= a

8 =
(v
f

0.75)

Cross Mult

3

24 = v
f

0.75

.75

24.75 m/s = v
f

Solve:

v
f

= 24.75 m/s

19
)

What is the acceleration of a car that was traveling at 30 m/s and hit brakes to come to a stop in 1.7 s ?

Diagram: (Given + Unknowns)

a = ???

m/s
2

v
f

=0 m/s

v
i

= 30 m/s

t = 3 s

Δd =

Equation:

a =
(v
f

v
i
)

t

Substitute:

a =
(0

30)

1.7

Solve:

a =
-
17.6 m/s
2

20
)

From the position vs time graph

(left)
, draw the proper translation of a velocity vs time and acceleration vs
time g
raph

using the middle and right graphs
.

LABEL
SI
UNITS ON ALL GRAPHS ON THIS
AND THE FOLLOWING
PAGE

21
)

Describe the acceleration in the following situations:

a
.
Acceleration from 0 to 4 sec:

(negative acceleration)

b. Acceleration from 4 to 6 sec:

(zero acceleration)

c. Acceleration from 6 to 10 sec:

(positive acceleration)

0
2
4
6
8
10
0
0.5
1
1.5
2
Position

Time

Relationship between Position
and Time

-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
0
1
2
3
4
5
Velocity

Time

Relationship of Velocity vs Time

-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
0
1
2
3
4
5
Acceleration

Time

Relationship of Acceleration vs
Time

2
4
6
8
10
2
4
6
8
time
velocity
Use the

following Position vs
.

Time
graphs
next six
questions.
The reference point is at 0 m.

M
ultiple graphs are possible answers to these questions.
Graph

choices can be used more than once.

22
)
Which
of the following graph(s) shows motion with
constant non
-
zero acceler
ation? ____
A and B
_
________

23
)
Which of the following graph(s)
shows motion towards the reference point? ___________
C
__________

24
)
Which of the following graph(s) shows motion with positive constant velocity? _________
D
__________

25
)
Which of the following
graph(s) shows

motion where the object is speeding up? _
_______
B
__________

26
)
Which of the following graph(s) shows motion with no acceleration? _______
C and D
____________

27
)
Which of the following graph(s) shows motion with a negative changing velocity? ____
none
__
____________

28) Draw a velocity vs t
ime and an acceleration vs time graph that

would show a cat moving with constant velocity

in the positive direction.

0
0.5
1
1.5
2
0
0.5
1
1.5
2
Position

Time

Graph A

0
0.5
1
1.5
2
0
0.5
1
1.5
2
Position

Time

Graph B

0
0.5
1
1.5
2
0
0.5
1
1.5
2
Position

Time

Graph C

0
0.5
1
1.5
2
0
0.5
1
1.5
2
Position

Time

Graph D

-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
0
1
2
3
4
5
Velocity

Time

Relationship Velocity vs Time

-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
0
1
2
3
4
5
Acceleration

Time

Relationship Acceleration vs Time