Question

With its wheels locked, a van slides down a hill inclined at 22.0∘ to the horizontal.

Find the acceleration of this van if the hill is icy and frictionless.

Find the acceleration of this van if the coefficient of kinetic friction is 0.151.

Answer 1

so first you will need to find the normal force, (which is the force of the ground pushing up against the van, while being perpendicular to the ground.)
then you'll need to sum forces in the x-direction utilizing the normal force you got previously. which then will tell you the acceleration, because f=m*a

Answer 2

I believe the answer is sin(22) * gravity

Answer 3

for part B, the equation will look something like this
acceleration of gravity pulling it down hill - resisting acceleration from friction = answer
so,
sin(22)*gravity - ((0.151 * cos(22) * w)/w) = acceleration
I hope this helps!