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View Full Version : Kinetic Friction H E L P ! ! !


songokou77
Oct6-04, 01:36 PM
When mass M is at the position shown, it is sliding down the inclined part of a slide at a speed of 1.89 m/s. The mass stops a distance S2 = 1.85 m along the level part of the slide. The distance S1 = 1.25 m and the angle theta = 37.7 degrees. Calculate the coefficient of kinetic friction for the mass on the surface.

Well i kinda found a formula for this by changing the conservatiion of energy(K_f+U_f=K_i+U_i+W_nc).

The formula is mu_k=(-1/2*(V_i^2)-1/2*(g*h))/(g*S_total),

But I still dont get the right answer am I doing something wrong?

arildno
Oct6-04, 01:39 PM
Think again:
You haven't used the information that you are on an INCLINED plane!!

songokou77
Oct6-04, 02:16 PM
I used the incline plane to figure out h=Ssin37.7=0.26

arildno
Oct6-04, 02:48 PM
It's still wrong, you've used a frictional force: \mu{mg}
This is incorrect.
In addition, your signs are messed up