Question

A hockey puck is hit on a frozen lake and starts moving with a speed of 12.3 m/s. Five seconds later, its speed is 6.60 m/s.
(a) What is its average acceleration?
1 m/s2
(b) What is the average value of the coefficient of kinetic friction between puck and ice?
2
(c) How far does the puck travel during the 5.00 s interval?
3 m

Answer 1

(a) Acceleration is the change in speed (V2 - V1) divided by the time interval of the change (T = 5 s). In this case, it is negative.

(b)(Average friction force)*time = momentum change
M*g*mu*T = M(V1 - V2)

mu = (V1 -V2)/(g*T)

(c) Average speed * Time = (V1 + V2)*T/2