Question

In a shuffleboard game, the puck slides a total of 12 m before coming to rest. If the coefficient of kinetic friction between the puck and the horizontal board is 0.28, what was the initial speed of the puck?

1 : 8.1 m/s

2 : 29.0 m/s

3 : 6.5 m/s

4 : 7.3 m/s

Answer 1

The acceleration of the puck

$$a=\frac{v^2}{2d}= \frac{F}{m}\\ \frac{v^2}{2d}=\mu g$$

Hence

$$v=\sqrt{2\mu g d}=\sqrt{2\times 0.28\times 9.8\times 12}=8.1\:\rm m/s$$