Physics 7. Homework # 1

Due: 4/5

1) Mr. Barnum trained a flea so that every time he shouted “jump” the flea jumped. Mr. Barnum then performed the following experiment: he first removed all of the flea’s legs, then he shouted “jump”, but (alas!) the flea did not jump. He then hypothesized that fleas without legs cannot hear. An experiment that would test this hypothesis could be

a) He could separate the fleas into two groups and carefully cover the legs of the fleas in one group. Then he could repeat the experiment and see whether only the fleas without leg covers jump.

b) There is no way this statement can be tested

c) He could cut only some of the legs and see whether he needs to shout louder to get a jump

d) He could place the fleas in a vacuum and determine whether thy obey his command.

2) In which of the following statements Ockham’s razor is not used?

a) Buy our new vegetable oil Moozola made from herb cows like! This produce is shown to have half the cholesterol of other oils [supported by a bona-fide reference to an accurate study]

b) Reelect candidate Joe Doe! During his tenure school-children grades went up 20% in all standardized assessments [grades did go up, though he completely ignored schools during his term]

c) If you do not exercise you will die younger [supported by numerous accurate studies]

d) Travel Aero-Maybe! We might not get there, but it’s cheap! [no comment]

3) Assuming that everything is made out of fire, air, water and earth, what would you say is the dominant elements in lead, and why would you say so?

a) Mostly earth because when released it falls towards the center of the Earth

b) Mostly water because one can melt it and it then flows like a liquid

c) Mostly fire because even if exposed to fire very briefly it gets extremely hot

d) It is made neither of earth, fire, air nor water because even the Greeks knew lead is found on other planets and these planets do not move up or down but around the Earth.

4) An astronaut grabs a rock form Earth, flies to the Moon and, once there, he lets go of the rock. According to Aristotle, what would happen after he lets go of it?

a) It will start circling the Moon

b) It will fall towards the moon’s surface

c) It will fall towards the Earth

d) It will fly off into space