A 280 kg piano slides 4.3 m down a 30° incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction is 0.40. Calculate:

(a) the force exerted by the man,
(b) the work done by the man on the piano,
(c)the work done by the friction force,
(d) the work done by the force of gravity, and
(e) the net work done on the piano.

formula for each question??

3 answers

So it is moving, but not accelerating. The kinetic friction force PLUS the man's applied force (f) balances the component of weight down the ramp.

For part (a)
f + 280*g*cos30*0.40 = 280*g*sin 30
Solve for f

(b) -f*4.3 m = _ J
(c) -(friction force)*4.3 =
(d) M g sin 30 * 4.3 =
(e) zero. The piano's KE does not increase.

How do you find friction force

Ffr= ukFn