Question

1) Consider a box of mass m sitting on an inclined plane. The inclined plane makes an angle θ with the horizontal and the coefficient of static friction between the box and the surface is μ. What minimal condition must exist if the box is to accelerate down the incline?

A) mgsinθ < μFn

B) mgsinθ = μFn

C) mgsinθ > μFn

D) mgcosθ > π

2) You observe a packing crate sliding down a long, inclined ramp at constant velocity. Practically speaking, you can deduce that:

A) the force on the crate must be > 0

B) a frictional force is acting on it

C) the crate is weightless

D) the crate is empty

Answer 1