If superman in space throws a boulder with 10 times as much mass as himself, and the boulder leaves his hands at 100 m/s, how fast does superman recoil?

Question

A) 1000 m/s.
B) The same speed, 100 m/s.
C) 10 m/s.
D) None of these are correct.

Answer 1

1000 m = m v
v = 1000