A bench of mass 40 kg is brought from the first floor of the school to the second floor. The height difference between the floors is 3m.

What is the work done against the gravitational force if the bench is shifted from one room to another by pushing it across the floor?

In this part we have to find the amount of work done against the gravitational force when the bench is moved from one room to another by pushing it across the floor.

Now, in the previous part it is already mentioned that the gravitational force is acting downward or we can say towards the centre of the earth. While in this part the force is applied to move the body against the frictional force, there is no change in the height of the bench so, it is clear that the work is done against the frictional force not gravitational force.

Work done against gravitational force when the bench is moved from one room to another by pushing it across the floor = 0.

Note :- As there is no work done against the gravitational force but the work is done against frictional force.