physics
posted by Anonymous .
a 50kg object is suspended by a rope over a pulley which is connected to a large mass of 61.3kg. The mass rests on a 30 degree inclined ramp. The coefficient of kinetic friction between the block and the ramp is .15. What is the 50kg object's acceleration?

weight down the hill: 50g*SinTheta
friction on the plane= 50g*mu*CosTheta
now, assuming the block is going up the hill (friction in the direction of downhill)..
61.3g50g*sinTheta50g*CosTheta=mass*a
solve for a. 
would the acceleration be negative?

Yes, if it is defined positive downhill. I believe Bob left on the coefficient of friction mu in the CosTheta term of the last equation.