# Finding stopping distance given coefficient of kinetic friction and mass

#### disque

1. The problem statement, all variables and given/known data
Bobsled

A bobsled run leads down a hill as sketched in the figure above. Between points A and D, friction is negligible. Between points D and E at the end of the run, the coefficient of kinetic friction is µk = 0.4. The mass of the bobsled with drivers is 210 kg and it starts from rest at point A.

Find the distance x beyond point D at which the bobsled will come to a halt.

2. Relevant equations
PE=mgy
(delta)x = ½ v_o2/ mg

3. The attempt at a solution
I thought the bottom equation should be the right approach but I dont know how to find the velocity given the coefficient of kinetic friction and mass of the sled
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

#### Attachments

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#### tiny-tim

Homework Helper
A bobsled run leads down a hill as sketched in the figure above. Between points A and D, friction is negligible. Between points D and E at the end of the run, the coefficient of kinetic friction is µk = 0.4. The mass of the bobsled with drivers is 210 kg and it starts from rest at point A.

Find the distance x beyond point D at which the bobsled will come to a halt.
Hi disque! (I can't see the picture yet)

This is an energy question …

calculate the the work done by friction,

and use the work-energy theorem, which says that loss of energy equals work done. ### The Physics Forums Way

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