Physics 7 homework #2

        Due 4/14/09

 

1.      How do the heliocentric and geocentric hypotheses explain the fact that we see the Sun move across the sky?

a.       Both assume that the Earth is rotating

b.      Both assume that the sun moves around the Earth

c.       The heliocentric theory had no explanation. In the geocentric theory the Earth rotates around its axis

d.      In the geocentric theory the Sun moves around the Earth, in the heliocentric theory the Earth rotates around its axis

2.      Why were epicycles invented?

a.       To complicate the model so that only the initiated could understand it

b.      As an attempt to divorce cosmology from the influence of Aristotle

c.       To explain the retrograde motion of the planets

d.      To explain the motion of the sun across the sky

3.      The results of the experiments and observations of Erathostenes

a.       Supported the hypothesis that the Earth is flat

b.      Supported the hypothesis that the Earth is round

c.       Were in direct contradiction with the geocentric hypothesis

d.      Were in direct contradiction with the heliocentric hypothesis

4.      According to Kepler’s third law a planet 4 times farther form the Sun than the Earth will take

a.       8 years to go around the sun

b.      4 years to go around the sun

c.       2 years to go around the sun

d.      1 year to go around the sun

5.      According to Kepler’s 2nd law,

a.       Planets slow down when farther from the Sun and speed up as they approach

b.      Planets move at constant speed as they orbit the Sun

c.       Planets have random speeds as the orbit the Sun

d.      Planets speed up when farthest form the Sun and slow down as they approach

6.      Suppose you own a Moon rock. One day you take it out of its box and let it drop. Aristotle would predict that

a.       It would hover at a fixed height above the ground

b.      It would raise towards the Moon

c.       It would fall down to Earth.

d.      It would start circling the Earth

7.      If the Earth is rotating why is it that objects fall straight down and are not “fall behind”?

a.       Because the objects participate in the rotation of the Earth

b.      Because gravity pulls them down

c.       Because of the attraction from the Moon

d.      Because the wind pushes them in the right direction

e.       The Moon’s mountains should be too small to be seen

8.      Suppose the Earth is at the center of the universe as Aristotle claimed, then a Martian astronomer would see

a.       A stationary  Earth

b.      All the planets except the Earth move around Mars

c.       See the Earth move around Mars and all other celestial bodies move around the Earth

d.      All planets move around the Sun.

9.      If Aristotle were to see an object that is slowly spiraling down towards Earth (that is, it goes around and around the Earth coming closer and closer towards its surface) he would conclude that it is made of

a.       Only earth.

b.      Only a mix of earth and fire.

c.       A mix of the 5th element and earth.

d.      Only the fifth element.

10.  In the Copernican model an observer on Mars would see

a.       None of the planets exhibit retrograde motion

b.      All other planets move around the Earth

c.       A stationary Earth

d.      The Earth exhibit retrograde motion