For Questions 9-12, Draw the Force Diagram to Represent the Situation in the Middle Column

Newton’s Laws Review Show all work underneath the problem, then write the answer in the space provided. 1. State the 3 Laws of motion: 1st:

List the five attributes of a force:

You are in the middle of outer space away from any gravitational (assume that your gravitational force has no effect on the object) or frictional forces and you throw a rock. Answer questions 2-4. 2. The rock will do which of the following? a. Gradually speed up b. Gradually slow down c. Begin to fall d. Continue moving at a constant speed

Answer (2)______3. The rock’s tendency to do this is called… Answer (3)______4. This tendency of the rock to do this is determined primarily by its… Answer (4)______5. A ball is being whirled in a circle at the end of a string (clockwise). If the string breaks as shown on the diagram below which path will it take (A, B, C, D, or E)? Answer (5)______

6. What does this have to do with the First law? Explain! The skater drawn below has a mass of 55 kg. She is being propelled by a jet pack with a mass of 5 kg. Assume you don’t lose any mass as the fuel is consumed. Answer questions 7a and 7b. 7a. Assume that any resistance due to friction and air resistance is negligible. Complete the table below.

Force applied by Jet pack Mass (kg) Acceleration (m/s2) (N) 50 N 100 N 120 N 10 m/s2 20 m/s2

7b. Now given the amount of air resistance and friction (Resistant forces) on her complete the table below. Force applied Resistance forces Net force Acceleration 100 N 50 N 50 N 50 N 150 N 75 N 20 N 5 m/s2 600 N 10 m/s2 8. Below is a list of masses and accelerations due to gravity on different planets. Complete the following table. Acceleration due to Planet Mass of object Weight gravity Earth 40 kg 10 m/s2 Mars 50 kg 3.8 m/s2 Jupiter 5 kg 26 m/s2 Pluto 200 kg .61 m/s2

For questions 9-12, draw the force diagram to represent the situation in the middle column, then draw an arrow showing the direction the net force points in the last column. Label all forces! 9. A wrecking ball is held motionless by a cable. 10. A small child slides down a frictionless slide.

11. The weight pulls block A across a frictionless table.

12. A skydiver falls at constant velocity (include air resistance)

13. As a ball falls, consider one force to be the pull of the earth's mass on the ball. What is the Newton’s third law pair to this force? a. non-existent in this case. b. the acceleration of the ball. c. the pull of the ball's mass on the earth. d. air resistance acting against the ball. e. none of these.

14. A horse exerts 500 N of force on a heavy wagon, causing it to accelerate. What force does the wagon exert on the horse? a. 500 N. b. more than 500 N. c. less than 500 N. d. it’s not possible to tell.

For questions 15 - 20, it is possible to have MORE THAN ONE correct answer. Circle ALL correct answers that apply. For questions 15 – 18, refer to the diagram below. A student attaches a string to the block on the table, and pulls with a constant force on the block.

15. Which of the following forces act on the block? a. the force of gravity b. friction c. a normal force d. the applied force

16. Which of the following describes the motion of the block while it's on the table? The block a. speeds up for a bit, then moves at constant speed. b. accelerates constantly. c. slows down gradually to a stop. d. moves at constant speed. 17. When the block reaches point B, the string breaks. Which of the following describes the motion of the block? The block a. begins to slow immediately. b. continues to accelerate. c. moves at constant speed. d. continues at constant speed for a while, then slows down.

18. Eventually, the block reaches the edge of the table. After the block leaves the table, which of the following forces act on the block? (neglect air resistance) a. the force of gravity b. the force of motion c. a normal force d. kinetic friction *************************** 19. A block of dry ice resting on a table is given a brief push. A moment later, which of the following forces act on the block? a. the force of gravity b. friction c. the force of the push d. a normal force

20. Which of the following describes the motion of the block from question 19? The block a. accelerates constantly. b. continues at constant speed for a while, then slows down. c. slows down gradually to a stop. d. moves at constant speed.

21. You’re in the back of a friend’s pickup truck when it stalls on a hill. You jump out, get behind the truck and push with all your might (300 N). Still, the truck slowly rolls back down the hill. The force the truck exerts on you is: a. 300 N. b. less than 300 N. c. greater than 300 N. d. it’s not possible to tell

22. A 35 kg box is being pulled to the left with a force of 150 N. Friction is slowing the box down with a force of 80 N. a. Draw and label all forces acting on the box. B. What is the net force on the box? C. What is the acceleration of the box?

23.A 4600 kg helicopter accelerates upward at 2.0 m/s2. How many Newtons is the lift force exerted by the air on the propellers?

24. The maximum force that a grocery bag can withstand without ripping is 250 N. Suppose that the bag is filled with 20 kg of groceries and lifted with an acceleration of 5.0 m/s2. Do the groceries stay in the bag?

25. A student, standing on a scale in an elevator at rest, sees that his weight is 840 N. As the elevator rises, his weight appears to increase to 1050 N, then returns to normal. When the elevator slows to a stop at the 10th floor, his weight appears to drop to 588 N, then returns to normal. Draw a motion map for the student during his elevator ride. Determine the acceleration at the beginning AND at the end of the ride, before returning to normal. (You must draw 2 force diagrams, one for each case.)