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Motion & Force
Science 8
Laws 1 & 2 and app problems
Name:__________KEY____________________
#3
Date:________________
Hr:_____
1. Infer whether the inertia of an object changes as the object’s velocity changes.
Inertia depends on mass, and doesn’t effect the speed or direction of an object.
2. Explain why the net force on an object that is traveling at a constant speed in a straight line is
equal to 0N.
If there is no change in motion, then forces are balanced. When the forces are
balanced the net for is 0N. Constant speed and straight line indication that no change
in motion is being made.
3. What must be occurring to the forces on an object at rest?
If an object is at rest, and no change in occurring then the forces must be balanced.
4. If the mass of a helicopter is 5225 kg, and the net force on it is 16,500 N, what is the
helicopter’s acceleration?
Info given
What are you
asked to find?
Formula
Substitute and solve (show
work with units)
Answer that
includes
units
m= 5225 kg
F=16,500 N
Acceleration?
a=F/m
a = 16,500 N / 5225 kg
a=3.16
m/s/s
5. What is the net force on a dragster with a mass of 1200 kg if its acceleration is 31.23 m/s/s?
Info given
m =1200 kg
What are you
asked to find?
Force?
Formula
F=mxa
Substitute and solve (show
work with units)
F = 1200 kg x 31.23 m/s/s
Answer that
includes
units
F=37,476 N
a = 31.23
m/s/s
6. A car is being pulled by a tow truck. What is the car’s mass if the net force on the car is
6500N and it has an acceleration of 2.7 m/s/s?
Info given
What are you
asked to find?
Formula
Substitute and solve (show
work with units)
Answer that
includes
units
F = 6500 N
Mass?
m = F/a
m = 6500 N / 2.7 m/s/s
a = 2.7
m/s/s
m=
2407.41 kg
7. You push yourself on a skateboard with a force of 30 N and accelerate at 0.5 m/s/s. Find the
mass of you and the skateboard together.
Info given
What are you
asked to find?
Formula
Substitute and solve (show
work with units)
Answer that
includes
units
F= 30 N
a = 0.5
m/s/s
Total mass?
m = F/a
M = 30 N / 0.5 m/s/s
m= 60 kg
8. You push a book that has a mass of 2.0 kg so that it has an acceleration of 1.0 m/s/s. What is
the net force on the book?
Info given
m = 2.0 kg
a = 1.0
m/s/s
What are you
asked to find?
Force
Formula
F=mxa
Substitute and solve (show
work with units)
F = 2.0 kg x 1.0 m/s/s
Answer that
includes
units
F=2 N
Force & Motion
Science 8
Laws 1 & 2 and app problems
#3
Name:______________________________
Date:________________
Hr:_____
1. Infer whether the inertia of an object changes as the object’s velocity changes.
2. Explain why the net force on an object that is traveling at a constant speed in a straight line is
equal to 0N.
3. What must be occurring to the forces on an object at rest?
4. If the mass of a helicopter is 5225 kg, and the net force on it is 16,500 N, what is the
helicopter’s acceleration?
Info given
What are you
asked to find?
Formula
Substitute and solve (show
work with units)
Answer that
includes
units
5. What is the net force on a dragster with a mass of 1200 kg if its acceleration is 31.23 m/s/s?
Info given
What are you
asked to find?
Formula
Substitute and solve (show
work with units)
Answer that
includes
units
6. A car is being pulled by a tow truck. What is the car’s mass if the net force on the car is
6500N and it has an acceleration of 2.7
Info given
What are you
asked to find?
Formula
m/s/s?
Substitute and solve (show
work with units)
Answer that
includes
units
7. You push yourself on a skateboard with a force of 30 N and accelerate at 0.5 m/s/s. Find the
mass of you and the skateboard together.
Info given
What are you
asked to find?
Formula
Substitute and solve (show
work with units)
Answer that
includes
units
8. You push a book that has a mass of 2.0 kg so that it has an acceleration of 1.0 m/s/s. What is
the net force on the book?
Info given
What are you
asked to find?
Formula
Substitute and solve (show
work with units)
Answer that
includes
units