Chapter 3: Q 3-11 P (page 123)
Masses M and m attract each other with a gravitational force of magnitude F. Mass m is replaced with a mass 3 cm, and it is moved four times farther away. Now, what is the magnitude of the force?
Short Answer
The magnititude of the force is.
The mass of the Earth is
and their center-to-center distance is
Suppose that at some instant the Sun's momentum is zero (it's at rest). Ignoring all effects but that of the Earth, what will the Sun's speed be after one day? (Very small changes in the velocity of a star can be detected using the "Doppler" effect, a change in the frequency of the starlight, which has made it possible to identify the presence of planets in orbit around a star.)