Why would it be very hard to land aspeceship on saturn?

Why do astronauts in the space shuttle weigh less?

If anyone who can me with this hw? i would really appreciate it

In a game of pool, ball a is moving with a velocity v0 of magnitude v0 = 15 ft/s when it strikes balls b and c, which are at rest and aligned as shown. knowing that after the collision the three balls move in the directions indicated and assuming frictionless surfaces and perfectly elastic impact (that is, conservation of energy), determine the magnitudes of the velocities va, vb, and vc.