Which of the following statements about the work done by a force is incorrect?
Work is done by a force only if a body moves towards the direction of the applied force.
Work done by a body is equal to the amount of energy gained or spent by the body.
Work done by a force can be zero even if the body moves to a certain distance.
Work done by a force can be positive as well as negative.
Work done by a force is defined as the product of the force on a body and the displacement of the body along the line of action of the force. Therefore, it is not necessary that the body always moves towards the direction of the applied force. Even if a body moves opposite to the direction of the applied force, work is done by the applied force. This is because the displacement of the body is along the line of action of the applied force. In this case, the work done by the force is considered negative.
The correct answer is A.
Dear Experts, I can't understand this. How can it be not necessary that an objectalways moves towards the direction of the applied force?
If the above is correct, then please coin an example.
If we apply force in one direction and body will move opposite to that , its direction will be opposite to force applied.As in case of the upward motion of the ball, gravitation force is acting downward.So workdone will be negative here.