Physics 122 Worksheet: Forces

1. a) Which branch of motion studies describes an object's motion?
b) Which branch of motion studies explains why an object moves as it does?

2. Which branch answers these questions? a) how fast does it move? b) what made it speed up?

3. Define: force.

4. A force must involve contact between two objects. T, F.

5. List three effects of forces.

6. Although there are many examples of forces, they can all be grouped into just how many kinds?

7. Which force? a) holds together the nucleus b) occurs between charged particles c) exists between all matter d) involved with radioactive decay e) weakest f) strongest g) has the greatest range of effect.

8. Who summarized motion into 3 laws?

9. Which Law of Motion? a) a powerful engine makes a small car move quickly b) you stretch an elastic and feel it pulling back c) you lift up on a heavy object and feel its weight holding it down d) a rock chunklet coasts at a constant speed and direction (has the same velocity) through deep space e) a box sitting on the floor just stays there f) described with F = ma g) involves action-reaction forces h) an astronaut not anchored to the Shuttle pushes at an unanchored, heavy satellite and then she and the satellite drift apart i) a snowmobile carrying just the driver accelerates faster than when a passenger is on board.

10. Define: a) mass b) weight.

11. Explain which of these does not change in space.

12. Describe a situation in you might notice your weight.

13. Once a skydiver steps out of the airplane, why does she not fall faster and faster?

14. Define: inertia.

15. How does inertia affect? a) the force needed to move a heavy crate b) a knee injury to a fast moving, zig-zagging football player

16. Does the Shuttle astronaut in the question above escape the effects of inertia when she is maneuvering the large satellite?

17. In terms of overcoming inertia, why does a force accelerate a small mass more than a large mass?

18. In a common demo of the effect of inertia, a person places a coin on a card resting on the rim of a glass and then snaps their fingernail against the card. The card flies away and the coin falls into the glass. a) What is the assumed role of inertia in this case? b) Inertia is a bit of a misdirection in this case. What is a better explanation than inertia of why the penny does not accelerate with the card?
Hint: Would the card behave the same if the coin were glued to it?