Problem: A 70-kg astronaut pushes against the inside back wall of a 2000-kg spaceship and moves toward the front. Her speed increases from 0 to 2.4 m/s. Earth is the object of reference.
Part A: If her push lasts 0.30 s, what is the average force that the astronaut exerts on the wall of the spaceship?
Part B: If the spaceship was initially at rest, with what speed does it recoil?
I need help to find the average force that the astronaut exerts on the wall of the spaceship.