Question

Two persons manage to push a motorcar of mass 1200 kg at a uniform velocity along a level road. The same motorcar can be pushed by three persons to produce an acceleration of 0.2 ms-2 . With what force does each person push the motorcar? (Assume that all persons push the motorcar with the same muscular effort)

  • force and laws of motion CBSE Class 9
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Answer

Mass of the motor car = 1200 kg

Only two persons manage to push the car. Hence, the acceleration acquired by the car is given by the third person alone.

Acceleration produced by the car, when it is pushed by the third person,

a = 0.2 m/s2

Let the force applied by the third person be F.

From Newton’s second law of motion:

Force = Mass x Acceleration

F = 1200 × 0.2 = 240 N

Thus, the third person applies a force of magnitude 240 N.

Hence, each person applies a force of 240 N to push the motor car.

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