Chapter Assumptions
Unless stated otherwise, use the following values.rEarth = 6.38×10^6 m
MEarth = 5.97×10^24 kg
Chapter 12 Problems
Conceptual Problems
C.1 Compare planets farther from the Sun to those nearer the Sun. (a) Do the farther planets have greater or lesser orbital speed
than the nearer ones? (b) How does the angular speed of the farther planets compare to that of the nearer ones?
(a) i. Outer planets have greater orbital speed.
ii. Outer planets have smaller orbital speed.
iii. The orbital speed is the same.
(b) i. Outer planets have greater angular speed.
ii. Outer planets have smaller angular speed.
iii. The angular orbital speed is the same.
C.2 How much work is done on a satellite as it moves in a circular orbit around the Earth?C.3 According to Kepler's third law, the ratio T^2 /a^3 should be the same for all objects orbiting the Sun, since the factor 4ʌ^2 /GM is
the same. When this ratio is measured however, it is found to vary slightly. For instance, Jupiter's ratio is higher than Earth's
by about 1%. What are the two main assumptions behind Kepler's third law that are not 100% valid in a real planetary
system?C.4 From your intergalactic survey base, you observe a moon in a circular orbit about a faraway planet. You know the distance to
the planet/moon system, and you determine the maximum angle of separation between the two and the period of the moon's
orbit. Assuming that the moon is much less massive than the planet, explain how you can determine the mass of the planet.C.5 In a previous chapter, we used the equation PE = mgh to represent the gravitational potential energy of an object near the
Earth. In this chapter, we use the equation PE = íGMm/r. Explain the reasons for the differences between these two
equations: Why is one expression negative and the other positive? Is r equal to h?Section Problems
Section 0 - Introduction
0.1 Use the simulation in the first interactive problem in this section to answer the following questions. (a) Given two unchanging
masses, does the force between two masses increase, decrease, or stay the same as the distance between the masses
increases? (b) Given a fixed distance, does the force between two masses increase, decrease or stay the same as the
masses increase?
(a) i. Increase
ii. Decrease
iii. Stay the same
(b) i. Increase
ii. Decrease
iii. Stay the sameSection 1 - Newton’s law of gravitation
1.1 The Hubble Space Telescope orbits the Earth at an approximate altitude of 612 km. Its mass is 11,100 kg and the mass of
the Earth is 5.97×10^24 kg. The Earth's average radius is 6.38×10^6 m. What is the magnitude of the gravitational force that the
Earth exerts on the Hubble?
N(^242) Copyright 2007 Kinetic Books Co. Chapter 12 Problems