Physics Help?

Question

A box slides down a 31° ramp with an acceleration of 1.20 m/s2. Determine the coefficient of kinetic friction between the box and the ramp.

Answer 1

The net force is equal to mass time acceleration
looking at a FBD of the box, and summing the forces parallel to the surface of the ramp, we have

Gravity
m*g*sin(31)
and friction
-m*g*cos(31)*µk

setting up the equation F=m*a
m*g*(sin(31)-cos(31)*µk)=m*1.2
solve for µk
µk=0.458

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