In physical terms, explain why friction is a nonconservative force. Does it store energy for future use?
Solution 15DQ A force is said to be nonconservative if the work done by it depends on the path taken. Friction force is the example of a nonconservative force. A force is also said to be nonconservative if no energy is stored by the force. Suppose, a box has to be moved along a rough floor from a point A to another point B. A work will have to be done to overcome the force of friction to displace the box. Similarly if the box has to be brought back to the initial position of A, again the same amount of work will have to be done. This way there is always a finite work to be done along a closed path. This is why friction is a nonconservative force. A nonconservative force does not store energy for future use. In the box example given above, a part of energy in moving a body is lost due to the force of friction. This lost energy can never be utilized further.