# Problem 6-7 Friction coefficient - Part 2

A hockey puck travels $33\; m$ along an ice rink before coming to rest. Its initial speed was $11\;m/s$.

(a) What is the magnitude of the acceleration of the puck?
(b) What is the coefficient of kinetic friction between the puck and the ice?

Accumulated Solution

$v_x{^2} = v_{0x}{^2} + 2a_xx \\ a_x = -1.83\; m/s^2 \; \text{ (answer to (a))}$

$v_x{^2} = v_{0x}{^2} + 2a_xx \\ 0^2 = 11^2 + 2a_x(33) \\ a_x = -1.83\; m/s^2$

The minus sign means:

(A)   $\text{The object is slowing down.}$

(B)   $\text{The object is speeding up.}$

(C)   $\text{You can't have a negative acceleration.}$