Question about coefficient of kinetic friction

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To find the coefficient of kinetic friction between the ice and the puck, the initial speed of the puck is 5.0 m/s, and it comes to rest after traveling 20 m. The key is to use the relationship between frictional force and acceleration, applying Newton's Second Law (F=ma). By equating the frictional force to the mass times acceleration, the mass cancels out, allowing for the calculation of the coefficient of kinetic friction. The discussion highlights the importance of understanding the relationship between friction, acceleration, and the forces involved. This approach simplifies the problem, demonstrating that the mass is not needed to solve for the coefficient.
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A hockey player hits a puck with her stick, giving the puck an initial speed of 5.0 m/s. If the puck slows uniformly and comes to rest in a distance of 20 m, what is the coefficient of kinetic friction between the ice and the puck?

I know that this question must be rather easy, and that my mind has missed some logical leap in order to complete it.

Given the equation for kinetic friction (I can't format, so I'm not sure how to write this...)

f(sub k)=(mu)(normal force)

How can I solve for the coefficient (f sub k) without the mass? It seems that without the mass I am stuck.
 
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You have a force (friction) you need to find the acceleration. What happens when you equate your friction force to Newton's Third, F=ma?
 
Wonderful things happen.

I wonder why I didn't think of that. -blush-

Thank you!
 

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