Question

8 situations where no work is done

Answer 1

Situations where no work is done are 

1.If a block is moving on a smooth horizontal surface, no work is done.

2.You are carrying two bags in your hands and not moving . No work done.

3.A person holds a bundle of hay over his head for 30 minutes and gets tired. No work is done.

4.If you push a wall , but it does not move . No work is done.

5.You sit on a chair for hours . No work is done as there is no involvement of motion.

6.Earth rotates around the sun whole year but the work done by gravitational force on the Earth is zero.

7.Sleeping for many hours is also a example of no work done.

Answer 2

1.  When a table in on a floor at the same place for days together, there is no work done on the table by the gravitational force or normal reaction force.

2.  If I hold a book for some time, there is no work done on it by me.

3. If the pendulum of the clock is oscillating already, by itself,  there is no NET work done on it by the gravity in n oscillations.

4. Earth rotates around the Sun. In one Earth year the work done on the EArth by the gravitational force is zero.

5. I throw a ball up with a velocity, it goes up and comes down to the same location.  There is no NET work done on the ball.