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Coefficient of friction

how do you find the COF without mass?
Original post by Snowy_TM
how do you find the COF without mass?


Example?
Reply 2
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Snowy_TM
OP
10km/h
130m stopping distance
-25m/s deceleration
can you help me with the formula and explain how to do it for me please :smile:?
Original post by Snowy_TM
10km/h
130m stopping distance
-25m/s deceleration
can you help me with the formula and explain how to do it for me please :smile:?


F = frictional force
N = normal force

F = μN
normal force is the weight
F=μmg [1]

for a force accelerating a mass
F=ma [2]

combine [1] & [2]

ma=μmg

m cancels

a=μg

---
PS your numbers look iffy, check how you got a deceleration of 25m/s^2
(edited 7 years ago)
Reply 4
Avatar for Snowy_TM
Snowy_TM
OP
A=-u^2/2s
= 10^2/2*130
=0.384m/s
Can you put my results into an equation please to find the cof?

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