# Mark and David are loading identical cement blocks ontoDavid’s pickup truck. Mark lifts his block straight up fromthe ground to the truck, whereas David slides his block upa ramp on massless, frictionless rollers. Which statement istrue? (a) Mark does more work than David. (b) Mark andDavid do the same amount of work. (c) David does morework than Mark. (d) None of these statements is necessarilytrue because the angle of the incline is unknown. (e) Noneof these statements is necessarily true because the mass ofone block is not given.

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David’s pickup truck. Mark lifts his block straight up from
the ground to the truck, whereas David slides his block up
a ramp on massless, frictionless rollers. Which statement is
true? (a) Mark does more work than David. (b) Mark and
David do the same amount of work. (c) David does more
work than Mark. (d) None of these statements is necessarily
true because the angle of the incline is unknown. (e) None
of these statements is necessarily true because the mass of
one block is not given.

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Step 1

Mark and David are loading identical blocks but in two different ways.

Step 2

Mark is lifting the block straight up and hence there is no non-conservative force acting on the block. There is no non-conservative force acting in the case of David also as there rollers are considered to be massless and frictionless.

Step 3

Also, the change in kinetic energy is negligible. The total work done now turns out be simply the gravitational potential energy. The ...

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