Question

examples of positive,negative,zero work in physics
examples of positive negative and zero work in Physics ​

Answer 1

let a person lift and object up . The person applies a force f in the upward direction and the displacement of the object is also in the same direction. hence, work done by the person in lifting an object of is positive .

however in this situation a gravitational force due to the earth is acting on the object in downward direction that is the direction of force is opposite to the displacement of the object so work done by the force of gravity on an object being lifted up is negative.

A coolie with luggage on his head moves in horizontal direction on a railway platform the work done by coolie against the weight of luggage is zero because weight of luggage is acting vertically downwards and motion is along the horizontal direction as angle between the force of weight and displacement is 90 degree the work done is zero.
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