Mark and David are loading adentaical cement blocks on to David's pickup truck .Mark lifts his block straight up from the ground to the truck , whereas David slides his block up a ramp contining frictionless roles .Which statement is true about the work done on the block - Earth system?

Options

A. Mark does more work then David
B. Mark and David do the same amount of work
C. David does more work then mark
D. None of those statement is necessarily true because the angle of the inclined is incline is unknown

Answer

B

Explanation

Since the rollers on the rampused by Dabid were frictionless , he did not do any work over coming none consarvative any change in kinetic energy of the block (either becauese the speed was constant or was essentially zero during the lifting process ), The work done by the either Mark or Dabid equal the increases the gravitational potential energy of the block - Earth system as the block as the is lifted from the ground to the rack bad .Because they lift from the ground to the track bed verticle , they do equal amount of work