I have this physics problem that has simply been driving me crazy...heres the problem:(adsbygoogle = window.adsbygoogle || []).push({});

Jenn coasts down the hill on a sled, reaching the bottom with a speed of 7.0m/s. The coefficient of kinetic friction between the sled's runners and the snow is .05, Jenn has a mass of 62 kg, and the sled has a mass of 3.82 kg. How far do Jenn and the sled travel on the flat surface at the bottom of the hill before coming to rest?

first i set up my diagram

and i set the positives to be down (with gravity) and the direction the sled is going.

then i set up my free body diagram which has mg going down, normal force up, the force of the motion going in the direction of the thread, and kinetic force opposing the motion.

Then i added up the masses and got a total of 65.82kg. Then i continued to find my net forces which i got

Fy = mg - Fn (normal) = ma = 0

and

Fx = Fm (motion w/ the sled) - Fk.

Since i know mg = 645.04 i plugged that in.

Then i know that Fk = mue * mg so i got that Fk = .05.

From here i don't know where to go. Help would be greatly appreciated! Thanks a ton!

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# Homework Help: Help with Friction and newtons laws

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