1) A 96.6 lb box is sliding down a rough slope which is inclined at 32º to the horizontal, as shown. Take μs= 0.75 and μk = 0.60.

Assume the box is already moving down the slope.

(If it would not normally be moving, perhaps it was nudged)

a) What is the mass of the box?

b) What is the weight of the box?

c) Draw a Free-Body Diagram showing all forces and the expected direction of

acceleration.

d) Make an appropriate choice of x-y axes and indicate them on the Free-Body Diagram.

e) Using the Free-Body Diagram and Newton’s Law, find the normal on the box.

f) Calculate the friction force on the box. State explicitly whether this is static or kinetic friction.

g) Using the Free- Body Diagram and Newton’s Second Law, find the acceleration on the box.

h) Is the box speeding up or slowing down? Why?

**Subject Physics General Physics**