A 200g hockey puck travelling at 10m/s on snowy, rough, ice, glides to a stop in 25m. Calculate the kinetic mu of rubber/ice interface.

Answer 1

Use the kinematic relation:

vf^2 - vi^2 = 2ad

vf = 0 [full stop]

vi = 10 m/s

d = 25 meters

First find the acceleration, then get mu from the force and acceleration.

0 - vi^2 = 2ad

a = -vi^2 / (2d)

Plug in the numbers for vi and d and get the acceleration (a) in m/s^2. Note a is negative. Next,

F = ma

-(mu)mg = ma

mu = -a/g

Plug in the result for a and plug in g. You can finish from here. Note mu will come out positive since a is negative.