Question

Lien is pushing a box across a table. She used a force of 100 N to get the box moving. Which force did she overcome to get the box moving?
a)the downward force of gravity on the box
b)the upward force of the table on the box
c)the reaction force on the box
d)the push force on the box

Answer 1

I’ll decompose each answer. My guess is answer C

A.) The force of gravity acts downward on the box, it plays no role in the horizontal acceleration assuming friction is nonexistent.

B.) The normal force acts upward on the box, it also plays no role in the horizontal acceleration.

C.) The reaction force on the box would be talking about Newton’s 3rd law. The reaction force acts on Lien and not the box. So she herself would have to overcome that reaction force to get the box moving. I believe this is the right answer

D.) The push force would be the force she applied. She wouldn’t have to overcome her own force that correlated with the box. She’d have to overcome the reaction force like I explained in answer C.