A box, with a mass of $1\mathrm{.}0kg,$ is initially at rest on an inclined plane, which is at an angle

of $25$ degrees with respect to the horizontal. The coefficient of static friction between

the box and the surface is ${}_s=0\mathrm{.}60,$ and the coefficient of kinetic friction is ${}_k=0\mathrm{.}20.$

a$)$ Calculate the magnitude of the frictional force acting on the box.

b$)$ Will the box start moving downhill on the inclined plane?

c$)$ If the box starts moving downward, calculate the force required to stop it$.$ If the box does not start moving, calculate the force required to set it in motion on the inclined plane downward.