posted by Charlie .
A hockey puck is hit on a frozen lake and starts moving with a speed of 12.2 m/s. Ex- actly 6.70 s later, its speed is 6.20 m/s. The acceleration of gravity is 9.81 m/s2 . a) What is its average acceleration? Answer in units of m/s2
a=(V-Vo)/t = (6.20-12.2)/6.70=-0.896 m/s^2.