A 290 kg piano slides 4.3 m down a 30掳 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.
(a) Calculate the force exerted by the man.
(b) Calculate the work done by the man on the piano.
(c) Calculate the work done by the friction force.Calculate the work done by an object and the force (3 parts)?
The friction force is (0.40)290(9.8)cos(30) = 984 N in the same direction the man pushes.
The gravity force along the incline is 290(9.8)sin(30) = 1421 N down along the incline.
In order to prevent acceleration, the man must push with force 1421 - 984 = 437 N.
The work done by the man is -437(4.3) = -1879 J since the distance moved is opposite the direction of his force.
The work done by the friction force is -984(4.3) = -4231 J.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment