# Work-Energy with friction

1. Sep 30, 2008

A rope and pulley have negligible mass, and the pulley is frictionless. The coefficient of kinetic friction between the first block (8 kg) and the table is $$\mu$$=.250. The blocks are released from rest. USE THE ENERGY METHODS TO CALCULATE THE SPEED OF BLOCK 2 (6 kg) after it has descended 1.5 meters.

Basically there's a diagram: Block #1 rests on the table and is connected by a rope that goes through a pulley to block #2, which is hanging off the table.

E = K + U
W = FDcos$$\Theta$$ = $$\Delta$$E

$$\Sigma$$F = F(Tens) - F(fric)

Block #1:
E-initial = PE = (6)(9.8)(1.5)
E-final = KE = 1/2 (6) v^2

Block #2:
E-initial = PE = ?
E-final = KE = ?

F = F(tens) - (8)(9.8)(.25)

Whats the next step??