" Work done by force of static friction "

Work done by the force of friction

STATEEMNT-1 : Work done by frictional force is always either negative or zero. because STATEMENT-2 : Work done by the static friction on a system may be zero.

Assertion: Work done by the force of friction in moving a body around a closed loop is zero. Reason: Work done does not depend upon the nature of force.

Assertion: Work done by the force of friction in moving a body around a closed loop is zero. Reason: Work done does not depend upon the nature of force.

Why work done by force of friction is always zero ?

For a man walking on the floor, the force of friction between the floor and his feet accelerates him forword. What will be work done by the force of friction, postive, negative or zero?

A block of mass m is kept over another block of mass M and the system rests on a horizontal surface. A constant horizontal force F acting on the lower block produces an acceleration (F)/(2(m+M)) in the sytem. The two blocks always move together. Consider displacement d of the system. a. Find the work done by friction on bigger block. b. Find the coefficient of kinetic friction between the bigger block and the horizontal surface. c. Find the frictional acting on the smaller block. d. Find the work done by the force of friction on the smaller block by the bigger block. e. Find the work done by static friction on bigger block.

Assertion: Static frictional force is a self adjusting force. Reason: Force of static friction does not depend upon the mass of the body.

Assertion: Static frictional force is a self adjusting force. Reason: Force of static friction does not depend upon the mass of the body.