Posted by Frustrated on .
You are pulling a 60kg crate across a level floor with a rope. If a force of 200 N
on the rope gives the crate an acceleration of 2 m/s2, what is the force of friction
that the crate exerts on the floor?

Physics 
Elena,
ma=FF(fr)
F(fr)=F+ma = 200 +60•2 =320 N