# SPH 3U Kinematics Test - Chatt

Mechanics

Nov 14, 2013 (4 years and 8 months ago)

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IRHS SPH3U1

Forces Test

Name: ______________________

Note the following information;

G = 6.
6
7 x 10
-
11

N
.
m
2
/kg
2

R
earth

= 6.38 x 10
6

m

m
earth

= 5.98 x 10
24

kg

Acceleration due to gravity on Earth is = 9.80 m/s
2

Part A: Knowledge
-

M
ultiple choice, circle the letter of the best response

below. [10
-
K]

1

a

b

c

d

e

6

a

b

c

d

e

2

a

b

c

d

e

7

a

b

c

d

e

3

a

b

c

d

e

8

a

b

c

d

e

4

a

b

c

d

e

9

a

b

c

d

e

5

a

b

c

d

e

10

a

b

c

d

e

Part B: Inquiry
-

1.

An
astronaut of mass 200.0 kg (inc
luding space suit and jet pack)
,

initially at rest
in deep space has run
out of fuel for the jet pack. In order to get back to his shuttle, the astronaut removes the 85.0 kg jet pack
and pushes it to the right with a force of 100.0 N for 0.50 s

a.

Explain wh
en Newton’s first law is exemplified in the above scenario.

(there are
two

times when
this occurs)

b.

Explain when Newton’s Second law is exemplified in the above scenario.

c.

Explain when Newton’s Third law is exemplified in the above scenario.

d.

Calculate the
acceleration and final velocity of
both the astronaut and the jet pack.

/2

/2

/2

/4

/20
K

/29
A

/8
c

2. Det
ermine the acceleration of the 15
.0 kg mass below using a vector diagram.

3. A 4
0.0 kg mo
del rocket is launched from the earth’s surface. If the

rocket accelerates upwards at

6.50

m/s
2
,
calculate the thrust force exerted by the rocket’s engine. Be sure to include a

FBD .

4.
Aft
er this forces test Mr Kirkup escap
es his class in his 1200 kg car. The car engine exerts a force of

24,000
N but

the car also experiences kinetic friction. If the coefficient of kinetic friction is 0.356, calcu
late
the acceleration of Mr Kirk
up

s car.

/4

/4

/5

5.

a) Calc
ulate the weight of a 8
0.0 kg person stand
ing on the surface of the earth using two different formulas.

b) Suppose this 8
0.0 kg person only weighs 380 N. How far fro
m the earth ‘s surface is this
person?

6. A 60.0 kg
student on a
snowboard is

moving at a velocity of 11.6 m/s on horizontal snow.
He coasts

(no
applied force)

and

come
s to rest 18.0 m from his stating position.
Calculate the coefficient of friction betwe
en
the snowboard and the snow.

Be sure to include

a free body
diagram.

Hint: d =
v
2
2

v
1
2

2a

/6

/2

/2

7.
A 75.0

kg bobsled is pushed by a bobsl
edder with a horizontal force and a 50.0 N downward force.

If the coef
ficient of friction is only 0.17
0, and the bobsl
ed accelerates horizontally at 2
.80 m/s
2
,

calculate the horizontal pushing force. Be sure to include a Free Body Diagram.

/6

SPH 3U Multiple Choice Questions for Forces & Motion Unit

1. An object moving at a constant velocity must

a) have a net force acting upon it

b) eventually drop due to the force acting on it

c) not have a force of gravity acting on it

d)
have all the forces acting on it balance with each other

e) not have a force of friction acting on it

2
.
When a 1.0 kg steel ball and a 10 kg steel ball are dropped from a tower, both balls accelerate towards the
ground at the same rate. This is because

a) both balls are made of steel.

b) the force of gravity on each ball is the same.

c) no forces act on the balls while they are falling.

d) the ratio Unbalanced Force/ Mass (ie: F/m) is the same for both balls.

e) the forces acting on the balls are balan
ced.

3
. Action and reaction forces always occur in pairs. They do not cancel each other out because

a) the action force is greater than the reaction force.

b) the action and reaction forces act on different objects.

c) the action and reaction fo
rces act in the same direction.

d) the reaction force acts only after the action force is removed.

e) the reaction force is greater than the action force.

4
. Which of the following statements is
always

true?

a) If an object is at rest, no force
s act on it.

b) If an object is moving, an unbalanced force acts on it.

a)

If an object is moving, it has a natural tendency to come to rest.

b)

If an object is moving, it has a natural tendency to keep moving

c)

If an object is moving in a circle, no forces act
on it.

5. If a small unbalanced force acts on an object, the object

a) remains stationary

b) moves at a constant velocity

c) accelerates

d) comes to rest and remains at rest

e) moves with uniform motion

6. What is t
he unbalanced force acting in the diagram at

the right?

a)

2 N right

b)

5 N left

c)

4 N up

d)

3 N right

e)

none of the above

7. What is the acceleration for the cart shown in question #6?

a)

0.40 m/s
2

right

b)

0.40 m/s
2
left

c)

1.6

m/s
2

right

a)

1.6 m/s
2

left

b)

0.0 m/s
2

8. The diagram below represents a body moving along a horizontal surface with only two forces.

If the body is slowing down, then which of the following statements is correct.

a) F
1

> F
2

b) F
1

< F
2

F
1

F
2

c) F
1

= F
2

d) F
2

F
1

= 0

direction of motion

9
. The acceleration of an object can be doubled by

a)

doubling the object's mass.

b)

doubling the unba
lanced force.

c)

doubling the objects velocity.

d)

doubling the frictional forces.

e)

oiling the wheels of the object.

10. The downward force of gravity on an elevator is 10
4

N. The upward force acting on the elevator is

10
4

N. Which one of the followi
ng statements is true ?

a)

The elevator must be at rest.

b)

The elevator could not be at rest.

c)

The elevator is accelerating downwards.

d)

The elevator is accelerating upwards.

e)

The elevator could be moving downwards with a constant speed.

5 N
3 N
4 N
4 N
5.0 kg