posted by Keelia on .
You push a 4.6 kg block against a horizontal spring, compressing the spring by 27 cm. Then you release the block, and the spring sends it sliding across a tabletop. It stops 63 cm from where you released it. The spring constant is 250 N/m. What is the coefficient of kinetic friction between the block and the table?
Get the initial velocity Vo using conservation of energy.
(1/2)MVo^2 = (1/2)kX^2
(X = 0.27 m is the spring compression; k is the spring constant)
After you have Vo, use KE = work done to stop.
(1/2) M Vo^2 = Uk*M*g
Actually you can skip the Vo step and just use
(1/2)*k*X^2 = Uk*M*g
Solve for Uk, the kinetic friction coefficient