A refrigerator weighing 1500 N is to be lifted onto a truck bed that is 1.0 m above the ground. When pushed up a slanting ramp 2.0 m in length a force of only 750 N is required to move it at constant velocity. Comparing the work involved in lifting the refrigerator straight up to the work in pushing it along the ramp, there is

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Quizplus · Accepted Answer

The work done against gravity is the same in both cases because work is defined as force times distance in the direction of the force. When lifting the refrigerator straight up, the work done is $1500 \, \text{N} \times 1.0 \, \text{m} = 1500 \, \text{J}$. When using the ramp, the force is halved but the distance is doubled ($750 \, \text{N} \times 2.0 \, \text{m} = 1500 \, \text{J}$), resulting in the same amount of work.

A Refrigerator Weighing 1500 N Is to Be Lifted onto a Truck