Question

A .400 kg bead slides on a curved wire, starting from rest at point A. If the wire in problem 61 is frictionless between points A and B (down 5m) and rough between B and C (up 2m), and if the bead starts from rest at A, (a) find the speed at B. (b) If the bead comes to rest at C, find the loss in mechanical energy as it goes from B to C.

(a) (1/2)(0)^2 +(9.8m/s^2)(5m) = (1/2) vf^2 + (9.8m/s^2)(0m) = 9.90m/s
(b)?

Answer 1

I have no idea what the picture is, but you can use conservation of energy (as you have done) to solve it. The speed at C is zero, so you know the energy was lost to friction. Again, conservation of energy.