# Force and momentum question

1. Oct 19, 2014

### lynaa

1. The problem statement, all variables and given/known data
The strong man will push the two initially stationary freight cars of equal mass apart before he himself drops straight to the ground. Is it possible for him to give either of the cards a greater speed than the other? Why or why not?

2. Relevant equations
None this is a theory question.

3. The attempt at a solution
It is not possible for the strongman to push either of the cars with a greater speed than the other because when the man pushes against one car, he is using the other car as a brace. So the force of the man pushing on one car would create a reaction force against the second car.

I am not really sure this is the right answer. I don't completely understand this concept about action and reaction forces yet.

2. Oct 19, 2014

### rude man

That part is right.

Is the "reaction" force on the second car equal in magnitude to the force on the first car?

3. Oct 19, 2014

### lynaa

I think it should be because of Newton's third law? Or do I not understand how his law works as well?

4. Oct 19, 2014

### rude man

Correct.
Now, if the same force magnitude is applied to objects of differing mass, would you expect them to move with the same magnitude of acceleration?