Name: _____________________________
Period: _____
Pre-AP Physics Forces Test Review
Part 1: Free body diagrams
Draw free body diagrams on the rocks below. Label all of the forces. Remember to choose
from your list of forces with fancy names: (Weight, Tension, Normal force, Friction, or air
resistance).
Page 1 of 6
Physics Unit 3: Forces Test Review
Part 2: Conceptual Stuff
1. Inertia is a ________________ to change in _________________.
2. Inertia is dependent on the ________________ of an object.
3. The weight of an object is caused by _______________.
4. Susie Small finds that she weighs 300 N on Earth. Calculate her mass.
5. A bowling ball and golf ball are dropped from the same height. Which would hit the ground
first?
6. List the reaction force to the following action forces:
a. A person’s hand pushes against a wall.
b. Earth pulls on a falling apple with its gravity.
c. As a person walks, their foot pushes against the ground.
7. Harold is helping Marge move. If Harold pushes on a box with a force of 10 N to the right, and
Marge helps him by pushing with a force of 15 N to the right. What is the net force (sum of the
forces) on the box?
8. Now Harold becomes stupid and starts to push on the box with 10 N to the left. What is the net
force (ΣF) on the box?
Page 2 of 6
Physics Unit 3: Forces Test Review
9. What is the acceleration of the box is Harold pushes left with a force of 50 N and Marge pushes
right with a force of 50 N?
10. Bubba has a mass of 90 kg and is running with an acceleration of 1.5 m/s2. What is the net force
acting on Bubba?
11. A car with a mass of 900 kg is experiencing a net force (ΣF) of 1,500 Newtons. What is the
acceleration of the car?
12. A crane lifts a heavy object with a constant velocity. What is the net force (ΣF) acting on the
object? Why?
13. An object with a weight of 20 Newtons is pushed across a surface that has a coefficient of
friction (μ) of 0.255. What is the force of friction acting on the object?
14. A 30 kg puppy is pulled across a surface with a μ of 0.775. What force of friction is acting on the
puppy?
Page 3 of 6
Physics Unit 3: Forces Test Review
15. A rope attached to a sled containing a puppy is pulled with a force of 50 Newtons at an angle of
20o from the horizontal. What are the x and y components of this force?
Part 3: FBD Problems
For each problem draw a free body diagram and write ΣF=ma equations for both dimensions before
you solve!
16. A crate is pushed across a frictionless table by a force of 10 N. The mass of the crate is 5 kg.
a. Draw a Free Body Diagram showing all the forces acting on the crate.
b. Write ΣF=ma equations for both dimensions.
c. Find the acceleration of the block.
17. A 20 kg rock is suspended motionless from a string. What is the force of tension in the string?
18. A 20 kg rock is suspended from a string while being accelerated upwards at 2 m/s2. What is the
force of tension in the string?
Page 4 of 6
Physics Unit 3: Forces Test Review
19. A block is pulled by a horizontal force along a rough surface. The Force pulling the block is 75 N.
The mass of the block is 5 kg. The coefficient of friction (μ) between the block and the surface is
0.6. What is the acceleration of the block?
20. A mass on a table is attached by a string and pulley system to another mass hanging from the
edge of the table. If the μ of the table is 0.134, what is the acceleration of the system?
21. A 8.6 kg block slides down a ramp. What is the acceleration of the block as it
slides down the ramp?
22. What is the normal Force keeping the block from falling through the ramp?
Page 5 of 6
Physics Unit 3: Forces Test Review
Part IV: Circular Motion
23. If an object is being twirled on a string and the string breaks, describe the path of the
object.
24. A car is doing donuts in the parking lot! If the car completes two rotations in 12 seconds.
If the radius of the circle made by the car in the previous problem is 8 meters, what
direction is the car’s centripetal acceleration?
25. A 1200kg car negotiates a turn of radius 65 m when the coefficient of static friction is 0.6.
What is the maximum speed to avoid slipping?
Page 6 of 6