Finding coefficient of kinetic friction for a sliding hockey puck

[Joshw17_15]

A hockey puck on a frozen pond is given an initial speed of 20.0 m/s. If the puck always
remains on the ice and slides 115 min before coming to rest, determine the coefficient of
kinetic friction between the puck and ice.




[v = u + a*t
=> 0 = 20 - a* 115*60
=> a = 20/(115*60)

v^2 - u^2 = 2*a*S
=> S = 400*(115*60)/2*20



(1/2)*m*v^2 = u*m*g*S
=> u = (1/2)*v^2/S*g
=> u = (1/2) * 400/S*9.8

I use these equations and I can't seem to come up with right answer

 

[rock.freak667]

(1/2)*m*v^2 = u*m*g*S
=> u = (1/2)*v^2/S*g
=> u = (1/2) * 400/S*9.8

I use these equations and I can't seem to come up with right answer

This should give the correct answer.

1/2mv²=μmg(115)