Question

A car can decelerate at -3.36-m/s2 without skidding when coming to rest on a level road. What would its deceleration (in m/s2) be if the road is inclined at 8.6o and the car moves uphill? (Assume the same static friction coefficient.

Answer 1

on the incline
friction=mu*mg*costheta
but mu*mg=m*3.36 or mu=3.36/g
weight down hill: mg*sinTheta
net force down hill= weightdown+friction
= mg*sinTheta+3.36/g*mg*costheta
=mg(sinTheta+3.36costheata/g)

so acceleration would be net force/mass down the hill would be
g*sintheta+3.36cosTheta/g and if you want the deacceleration up the hill, it is the negative of that.

Answer 2

I keep getting the wrong answer. i must be putting it in my calculator wrong.