posted by Henry .
A 60 kg block slides along the top of a 100 kg block with an acceleration of 3.0 m/s2 when a horizontal force F of 320 N is applied. The 100 kg block sits on a horizontal frictionless surface, but there is friction between the two blocks.
(a) Find the coefficient of kinetic friction between the blocks.
(b) Find the acceleration of the 100 kg block during the time that the 60 kg block remains in contact.
F(friction) = u*N
F(net)=> F - (u*m*g)=m*a
-(u*m*g) = m*a - F
-> u = - (m*a - F)/(m*g)
u = -(60kg*3.0m/s2 - 320N)/(60kg*9.81m/s2)
sorry, not sure how to do part B