- #1
OttoVon
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Homework Statement
The record speed for grass skiing was set in 1985 by Klaus Spinka, of
Austria. Suppose it took Spinka 6.60 s to reach his top speed after he
started from rest down a slope with a 34.0° incline. If the coefficient of
kinetic friction between the skis and the grass was 0.198, what was the
magnitude of Spinka’s net acceleration? What was his speed after 6.60 s?
The answer is:
a=3.87m/s^2
For the speed after 6.60s
velocity final=25.5m/s^2
What we Have
Time: 6.60s
Degree: 34
mg:?
n:?
M:0.198
From rest: V initial = 0 m/s
a=?
Speed after: 6.60s
Homework Equations
Friction=Mn
Efx:
Efy:
The Attempt at a Solution
This is what I did so far:
EFx: Friction-mgsin(34)=max
EFy:Normal Force-mgcos(34)=may
Added the mg's to the other side
Friction=mgsin(34)+max
Normal Force=mgcos(34)+may
Then plugged into the equation to find friction friction=(0.198)(normal force)
mgsin34+max=(mgcos34+may)(0.198)
The problem is that everything will cancel out so that is preventing me from finding acceleration