1. What is force? Identify several of the forces that are acting on or around you right now.

2. A person places a book on the roof of a car and drives off without remembering to remove it. As the book and the car move down a street at a steady speed, two horizontal forces are acting on together the book. What are they?

3. A person places a hand on a closed book resting on a table and then presses downward while pushing forward. Either the book slides across the table or the hand slides across the book. What determines which event happens? Which type(s) of friction is (are) involved?

4. A woman is riding on a train while watching the display on her GPS unit. She notices that both the "speed" and the "direction" readings are not changing. What can the she conclude about the net force acting on the train car?

5. Two astronauts in an orbiting space station "play catch"

(throw a ball back and forth to each other). Compared to playing catch on Earth, what effect, if any, does the "weightless" environment have on the process of accelerating (throwing and catching) the ball?

6. A single-engine airplane usually has its propeller in the front. Ocean freighters usually have their propeller(s) in the rear. From the perspective of Newton's second law of motion, is this significant?

7. What is the international system of units (SI)?

8. Describe the variation of the net force on and the acceleration of a mass on a spring as it executes simple harmonic motion.

9. Explain how the change in the force of air resistance on a falling body causes it to eventually reach a terminal speed.

10. At least two forces are acting on you right now. What are these forces? Describe the relationship between the size and direction of these two forces.

11. How is Newton's third law of motion involved when you jump straight upward?

12. If suddenly the value of G, the gravitational constant,

increased to a billion times its actual value, give several examples of the kinds of things that would happen. (Think locally as well as globally.)

13. In the broadest terms, what causes tides?

14. We have studied four different laws authored by Sir Isaac Newton. For each of the following, indicate which law is best for the task described. (a) Calculating the net force on a car as it slows down. (b) Calculating the force exerted on a satellite by Earth.

(c) Showing the mathematical relationship between mass and weight.

(d) Explaining the direction that a rubber stopper takes after the string that was keeping it moving in a circle overhead is cut.

(e) Explaining why a gun recoils when it is fired. (f) Explaining why a wing on an airplane is lifted upward as

it moves through the air.

15. Six identical cars are towing identical trailers at constant, albeit different, speeds along level roads in the desert. The trailers carry different loads, so their masses vary. The circumstances of each vehicle are shown here. Using the letter identifiers, rank the difference between the magnitude of the force exerted by the car on the trailer and the magnitude of the force exerted by the trailer on the car for each situation from greatest to least. If any situations have the same difference, give them the same ranking. Explain your reasoning in forming your rankings.

(a) Trailer load 5 1000 kg; vehicle speed 5 20 m/s

(b) Trailer load 5 2000 kg; vehicle speed 5 20 m/s

(c) Trailer load 5 4000 kg; vehicle speed 5 40 m/s

(d) Trailer load 5 4000 kg; vehicle speed 5 10 m/s

(e) Trailer load 5 2000 kg; vehicle speed 5 10 m/s

(f) Trailer load 5 1000 kg; vehicle speed 5 10 m/s