posted by Alexandra .
A 20.0kg mass is placed a the top of a 3.5m long, 15degree ramp. When released from rest, the mass accelerates down the ramp. The frictional force acting on the mass is 11.0 N. What is the velocity of the mass at the bottom of the ramp.
I would compute the kinetic energy at the bottom as (P.E. loss) - (work done against friction). Then use KE to get velocity.
Work done against friction is 3.5 * 11 -= 38.5 J
P.E. loss is M g H = 20*9.81*3.5 sin 15 = 50.8 J
K.E. at bottom = 12.3 J = (1/2) M V^2
Solve for V