CID# _________________ Quiz #8
Physics 121 Monday, June 9, 2008
1. The SI units of the universal gravitation constant, G, are (a) N kg-1, (b) N m2 kg-1, (c) N m2 kg-2, (d) N m kg-2.
2. True or False? The gravitational force associated with a spherically symmetric object is as if the entire
mass of the body were located at its center. (a) true, (b) false.3. Henry Cavendish is known for having been the first person to (a) express the universal law of gravity in a
quantitative fashion, (b) quantitatively and accurately describe the motions of the planets about the sun, (c)
determine the value of the universal gravitational constant, G.4. The gravitational acceleration g (a) increases with altitude (b) decreases with altitude, (c) is constant,
independent of altitude, (d) none of the preceding.
5. When doing celestial mechanics the preferred use of the arbitrariness in the gravitational potential energy
is to set its value equal to zero when two interacting bodies are (a) in contact at their surfaces, (b) in circular
orbits with a separation of 1.0 astronomical units (the earth-sun separation), (c) separated by a distance
equal to the radius of Pluto's orbit, (d) infinitely far apart.