Name _______________________________________________________ Due date ______________
Chapter 2: Newton’s First Law of Motion
Physics
19 pts
1. A ball is rolling across the top of a billiard table and slowly rolls to a stop.
a. How would Aristotle interpret this observation?
b. How would Galileo interpret this observation?
7. A space probe may be carried by rocket into outer space.
What keeps the probe going after the rocket no longer pushes it?
12. In tearing a paper towel or plastic bag from a roll, why is a sharp jerk more effective than
a slow pull?
14. a. Why do you lurch forward in a bus that suddenly slows?
b. Why do you lurch backward when it picks up speed?
c. What law applies here?
18. Consider a pair of forces, one having a magnitude of 20N and the other 12N.
a. What maximum net force is possible for these two forces?
b. What is the minimum net force possible?
20. When a ball is tossed straight up, it momentarily comes to a stop at the top of its path.
Is it in equilibrium during this brief moment? Why or why not?
24. Nellie Newton hangs at rest from the ends of the rope as shown.
How does the reading on the scale compare to her weight?
25. Harry the painter swings year after year from his bosun’s chair.
His weight is 500N and the rope, unknown to Harry, has a breaking point of 300N.
a. Why doesn’t the rope break when he is supported as shown at the left below?
One day Harry is painting near a flagpole, and, for a change, he ties the free end of the rope
to the flagpole instead of to his chair as shown at the right.
b. Why did Harry end up taking his vacation early?
29. As you stand on the floor, the floor exert an upward force against your feet.
How much force does it exert?
Why are you not moved upward by this force?
39. The chimney of a stationary toy train consists of a vertical spring gun that shoots a steel ball
a meter or so straight into the air... so straight that the ball always falls back into the chimney.
a. Suppose the train moves at constant speed along the straight track. Do you think the
ball will still return to the chimney if shot from the moving train?
b. How about if the train gains speed along the straight track?
c. How about if it moves at a constant speed on a circular track?