A student pushes a 200-lb box of books across the floor. The coefficient of kinetic fricti...

A student pushes a 200-lb box of books across the floor. The coefficient of kinetic friction between the carpel and the box is μk = 0.15.

(a) If he exerts the force F at angle α = 25°, what is the magnitude of the force he must exert to slide the box across the floor.

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(b) If he bends his knees more and exerts the force F at angle α = 10°, what is the magnitude of the force he must exert to slide the box?