The kinetic friction force acting on a sliding body moving in a straight line is constant, but it is non-conservative. Explain.

What is the direction of frictional force actiog on a body moving or sliding towards east ?

If a force is applied at an angle to a body moving along a straight line:

The power supplied by a force acting on a particle moving in a straight line is constant. The velocity of the particle varies with the displacement x as :

The power supplied by a force acting on a particle moving in a straight line is constant. The velocity of the particle varies with the displacement x as :

Friction is non-conservative force. How ?