Alex and john are loding adentical cabinates onto a truck .Alex lifts his cabinet strainght up from the ground to the bed of the truck , whereas john slides his cabinet up a rough ramp to the truck .which statement correct about the work on the cabinet- Earth system ?

Options

A. Alex and john do the same amount of work
B. Alex does more work then john
C. john does more work then alex
D. None of those statement is necessarily true because the force the friction is unknown

Answer

C

Explanation

Assuming that the cabinate has negligible speed during the operition , all of the work Alex does is used in inc reasing the gravitational potential energy of the cabitane - earth system .However in addition to increasing the gravitational potential energy of the cabitane - earth system by the same amount as Alex did . John must do work overcoming the friction between the cabinet and ramt . This means the total work done by john is greater than that done by Alax .