Class 22, ICA #18, October 14.

There were 9 clicker questions. For questions
1, 2, 4, 5, 6, 7, 8, 9, you got 1 mark for answering at all.
For question 5, you got an extra mark for getting it right.
For question 3, I didn't count at all.
There were a total of 9 marks possible.
The clicker questions count for a total of 3 points toward your
course grade, so your points for the day = # of marks * (3/9).




Clicker Question #1: Double the distance between two balls. 
What happens to the gravitational force?

E. It's cut down to a quarter.


Clicker Question #2: Double the distance, but quadruple the mass
of one of the balls. What happens to the gravitational force?

C. It stays the same.


Clicker Question #3, #4, #5: Fiendishly clever alien shrinks our
planet to half its diameter, but keeps the same mass. What
happens to our gravity?

A. gravity would be stronger.

(For #3, I didn't count it at all since some people ran out of time.
 For #4, I counted just whether you answered. #5 was the revote
 after discussion.)


Clicker Question #6: Moon is 1/4th diameter of Earth, but has
lower gravity. So its mass must be:

C. smaller than Earth's


Clicker Question #7: Where would the spaceship feel the same
gravitational force from Earth as it feels from the Moon?

C.


Clicker Question #8: You feel no gravitational force at the
location shown between Earth and Planet X. Planet X's mass is

A. bigger than Earth's.


Clicker Question #9: At the location shown between Earth and Planet Z,
you start falling back toward Earth. Planet Z's mass is

B. smaller than Earth's.