SSC MTS EXAM

SSC

PHYSICS

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

How much work is done by a motor that lifts a train car on El Toro to the top of a 70-meter hill using a force of 15, 000 N?

A	1, 000, 000 J
B	214.29 J
C	1, 050, 000 J
D	105, 000 J

Explanation:

Detailed explanation-1: -So the work by the cable is force of friction plus m g multiplied by the displacement. So that’s 100 newtons of friction plus 1500 kilograms, mass of the elevator, times 9.8 newtons per kilogram and then all of that is multiplied by four g meters giving us 5.92 times ten to the five joules of work done by the cable.

Detailed explanation-2: -According to the Work-Energy theorem or the relation between Kinetic energy and Work done-the work done on an object is the change in its kinetic energy. Hence, the work to be done to increase the velocity of a car from 30km/h to 60km/h is 156250 joule, if the mass of the car is 1500 kg.

Detailed explanation-3: -The total work done on the lift is the work done by the net force exerted on the car during this process. Therefore, total work done on an elevator car is zero.

There is 1 question to complete.