Two skaters stand together on frictionless ice. The women (57 kg) pushes the man (81 kg) with a force of 85N. How much force did the man push the women with?

Question

What is the women's resulting acceleration? What is the mans resulting acceleration?

Answer 1

By Newton's 3rd law, the force of the man on the woman must be equal and opposite to the force of the woman on the man, so it must be 85 N, but in the opposite direction.  You can call it -85 N.

 

a = F/m

 

Woman:

 

a₁ = (-85 N)/(57) kg ≅ -1.49 m/s²

 

The minus sign just means it is in the opposite direction as the force applied by the woman on the man, which I took to be the positive direction.

 

Man:

 

a₂ = (85 N)/(81 kg) ≅ 1.05 m/s²