Posted by Bridge on .
A box of books weighing 323 N is shoved across the floor by a force of 477 N exerted downward at an angle of 35° below the horizontal.
(a) If μk between the box and the floor is 0.51, how long does it take to move the box 4.80 m starting from rest?
(b) What is the maximum coefficient of kinetic friction between the box and the floor that allows the box to move from this applied force.

Physics help! 
jjcjb,
Anyone know how to do this