Physics
posted by wendlen .
A hockey puck is hit on a frozen lake and starts moving with a speed of 13.80 m/s. Exactly 6.7 s later, its speed is 7.10 m/s.
a) what is the puck's average acceleration?
b) what is the coefficient of kinetic friction between the puck and the ice?

acceleration=changevelocity/time
forcefriction=mass*a you know a, and mass
force friction=mu*mg
mu*g=a
solve for mu.