In outer space there is no gravity or air. An astronaut pushes with an equal force of 25 N on a 2 kg moon rock and on a 4 kg moon rock.
A) Both rocks will push back at the astronaut with 25 N
B) Since the astronaut is weightless, he cannot push on the rocks
C) Since both rocks are weightless, they do not push back on the astronaut
D) The 4 kg rock pushes back on the astronaut twice as hard as the 2 kg rock
E) Since both rocks are weightless, they will have the same acceleration

Question

In outer space there is no gravity or air. An astronaut pushes with an equal force of 25 N on a 2 kg moon rock and on a 4 kg moon rock. 
A) Both rocks will push back at the astronaut with 25 N
B) Since the astronaut is weightless,  he cannot push on the rocks 
C) Since both rocks are weightless, they do not push back on the astronaut
D) The 4 kg rock pushes back on the astronaut twice as hard as the 2 kg rock
E) Since both rocks are weightless, they will have the same acceleration

jamesj · Answer

What is Newton's 3rd law of motion? That will give you the answer to this question.

jamesj · Answer

Third law: When a first body exerts a force F1 on a second body, the second body simultaneously exerts a force F2 = −F1 on the first body. This means that F1 and F2 are equal in magnitude and opposite in direction.

Hence which is the only possible correct answer out of A - E?

jamesj · Answer

well, what do you think?

anonymous · Answer

A