A wet bar of soap slides down a ramp 5.3-m long inclined at 4.9o. How long (in seconds) does it take to reach the bottom, assume the coefficient of kinetic friction is 0.04.

Answer 1

friction force=m*g*costheta*mu
gravity force= m*g*sintheta
net force=gravity-friction
= mg(sintheta-mu*costheta)
but that equals m*acceleration
so acceleration a= g(sintheta-mu*costheta)
vf^2=vi^2+2ad vi=zero
solve for vf, you have a and d
average velocity= vf/2
time = distance/averagevelocity