Question

plz answer fast...

I have exam tomorrow....​

Answer 1

a) 1)The resultant force should not be zero

2) The body should be displaced due to net force.

3) The angle between force and displacement should not be zero.

b) When the displacement is in direction of force then it is positive work done.

ex- hitting a cricket ball, kicking a football etc.

c) When the displacement is in the opposite direction of the force then the work done is negative.

ex- applying brakes in a moving cycle, Applying brakes in a fast moving bus etc.

d) When the net force acting on a body is not the cause of displacement of the body or the net force is zero or the angle between the force and displacement is 90 then the work done is zero.

ex - Carrying a box on head and moving forward , coming back to the initial position after some time etc.