posted by bob .
A man pushes on a piano of mass 180 so that it slides at a constant velocity of 12.0 down a ramp that is inclined at 11.0 above the horizontal. No appreciable friction is acting on the piano. Calculate the magnitude and direction of this push
A. if the man pushes parallel to the incline,
We take the upward direction to be positive and downward one to be negative. The sign of the force should be entered correctly.
B. if the man pushes the piano up the plane instead, also at 12.0 parallel to the incline,
if the man pushes horizontally, but still with a speed of 12.0 .