Name ___________________________________ Hr ________ Date



Unit 4 – Forces and Motion

Test Review

The Unit 4 Test Date: __________________________________________

Directions: Answer the questions below on a separate sheet of lined paper. All answers must be handwritten. Please show ALL work and all equations used during calculations.

1. Define the term force. What is the SI unit for force?

2. What two ways can the SI unit for force be written?

3. Describe what happens to an object in each of the following situations:

a. An unbalanced force acts on the object

b. A pair of balanced forces act on an object in opposite directions

c. A net force of zero acts on an object

4. Describe the following forces:

a. Static friction

b. Sliding friction

c. Gravitational

d. Electromagnetic

e. Nuclear

5. Which of the above forces are in “direct contact” with objects? Which act at a distance?

6. Explain what happens to a sky diver in terms of gravity and air resistance after jumping out of an airplane.

7. Why would a flat sheet of paper and a wad of paper with the same mass not fall through the air at the same rate?

8. Write each of Newton’s Laws of Motion and give an example of each.

9. The property of matter that resists changes in motion is called _______________?

10. What would happen if you were carrying a tray of marbles and then had to stop suddenly?

11. Write the formula for weight. If the force of gravity on the moon is 1/6th the force of gravity on Earth, calculate the weight of a 150 kg astronaut on each planet.

12. Write the acceleration formula using the circle diagram.

13. Use the formula F = ma to solve the following problems:

a. How much force is needed to accelerate a 1000 kg cat at a rate of 3 m/s2?

b. If a 70 kg swimmer pushes off of a pool wall with a force of 250 N, at what rate will the swimmer accelerate from the wall?

c. A dancer lifts his partner above his head with an acceleration of 2.5 m/s2. The dancer exerts a force of 200 N. What is the mass of the partner?

14. If the force that propels a cannonball forward from a cannon is 500 N, how much force will move the cannon backward? Think about the Third Law….

15. Draw a diagram representing the following and solve for the net force and direction acting on the object:

a. A crate is being acted on by a force of 30 N to the left and 50 N to the right.

b. A crate is being acted on by a force of 100 N north and 30 N south.

c. A crate is being acted on by a force of 15 N east and 15 N west.

16. Determine if the following statements are true or false. If false, write the term that makes the statement true.

a. F = ma represents Newton’s second law of motion.

b. The force of gravity acting upon an object is the object’s mass.

c. To every action force, there is an equal and opposite reaction force is the law of conservation of momentum.

d. Air resistance acts in the opposite direction to that of an object in motion.

17. What are the different types of motion? How do they differ?

18. What Type of motion is this?

19. What is the difference between mass an weight? What is the equation for weight?

20. A pitcher in a professional baseball game exerts a force of 65.0 N to throw a ball. If the baseball has a mass of 0.145 kg, what is its acceleration?

21. A house is lifted from its foundations onto a truck for relocation. The unbalanced force lifting the house is 2850 N. If this force causes the house to accelerate at a rate of 3 m/s2, what is the mass of the house?

22. A device at Sandia Laboratories in Albuquerque, New Mexico, uses highly compressed air to accelerate a small metal disk to supersonic speeds. Suppose the disk accelerates at a rate of 15.8 m/s2. If the disk has a mass of 0.20 g, what is the unbalanced force on the disk?

Review your free body diagrams that we did in class to study for the free body diagram portion.

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