Sat March 12, 2011 By: Rohan Mehra

While moving we are applying force in the backward direction and moving in the forward direction.So is the work done by us negative?

Expert Reply
Sat March 12, 2011
Dear student,
when a car is moving on a road, there will be a frictional force applied by the road on the. There will be work done by the frictional force on the car. What is the work done on the road by the car? From Newton’s third law we can say that to every action, there is an equal and opposite reaction. Thus the force applied by the road on the car will be equal and opposite to the force applied by the car on the road. Since, there is no displacement of the road, there  will be no work done on the road.
Yes, work done by friction is positive.
Hope this helps.
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