posted by polo Q on .
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?
(b) What is the average value of the coefficient of kinetic friction between puck and ice?
(c) How far does the puck travel during the 5.00 s interval?
(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