Unit 6, Quiz
Gravitation and Satellite Motion
1. Which one of the following best describes the property
of speed for a planet orbiting the Sun?
a. greatest when closest
b. greatest when furthest away
c. independent of the distance of orbit
d. determined mainly by the planet's mass
2. An object has a mass 0.5 kg. It is transported to the
surface of Planet X where the object's weight (Fgrav) is
measured to be 20 N. The radius of the planet is 4 x
106 m. Determine the acceleration of gravity on
Planet X. PSYW
3. Two objects attract each other with a force of gravity
(Fgrav) of 24 N. If the distance separating the objects is
tripled and the masses of both objects are doubled, then
what is the new force of gravitational attraction? Show some
organized work (not scribbles) to earn some partial
4. Frieda Inhibitions, who has a mass of 55 kg, drools as
a Ferrari cruises past her. The Ferrari has a mass of 1200
kg. At closest approach, Frieda and the Ferrari are
separated by only 4.0 m. Calculate the force of
gravitational attraction between Frieda and her Ferrari?
5. According to Kepler's third law - the Law of harmonies
- the period (T) of orbit squared divided by the average
radius (R) of orbit cubed is the same for all planets. That
is, T2/R3 = constant. From this fact,
one might conclude that _____.
a. every planet orbits the sun in the same
amount of time
b. every planet orbits the sun at the same distance
from the sun
c. the planets furthest from the sun take more time to
orbit the sun
d. the planets furthest from the sun take less time to
orbit the sun
e. ... nonsense! None of these statements are
6. Astronauts orbiting the earth in the space shuttle
experience a force of gravity which is
a. several times greater than the Fgrav
experienced on Earth's surface
b. several times smaller than the Fgrav experienced on
c. a fraction greater than the Fgrav experienced on
d. a fraction smaller than the Fgrav experienced on
e. ... nonsense! Orbiting astronauts do not experience
any gravitational pull from the earth.
7. Choose the one best means of completing the following:
Newton discovered gravity ____.
a. while picking apples in his family orchard
b. while orbiting earth on his space shuttle
c. while investigating the reasons for why elderly men
develop "beer bellies"
d. while attempting to clean up his daughter's running
e. ... nonsense! Newton did not discovery gravity; he
discovered that gravity was universal.
8. Kepler's second law of planetary motion is the law of
equal areas. According to this law, _____.
a. all planets have equal areas when viewed from
a position on the sun
b. the surface area of the sun looks the same (and
even has the same area) when viewed from all planets
c. if a planet were a sun, then its area would be
d. all equal planets have the same sun.
e. if all planets were equal, then they would also be
f. all planets travel the same speed when moving along
their orbital path around the sun.
g. a planet travels fastest along its orbital path
when closest to the sun.
9. Using complete sentences, explain why an astronaut on
the orbiting space shuttle feels weightless.
10. Using complete sentences, compare a satellite which
is orbiting the earth to a baseball hit from the bat of
Sammy Sosa. In terms of physics principles discussed in this
a. What do they have in common?
b. In what sense are they different?
c. Why does the baseball land on Waveland Avenue and
the satellite never reach the earth?
The diagram at the right shows a satellite orbiting the
Earth in an elliptical path in a clockwise direction.
a. Draw a vector representing the velocity of
the object at position A.
b. Draw a vector representing the force on the object
at position D.
c. Draw a vector representing the accel'n of the
object at position C.
d. At which of the four positions is the satellite
moving fastest? ____
e. Fill in the work-energy bar chart shown below.