Question

A heavy drum is to be loaded onto a truck. Ravi chose the plank A while Hamid chose the plank B. Rahi did not use a plank at all.

1. Who would find the drum heaviest to load?
2. Who would find it lightest?

Which one of the planks A and B is longer?

 Which one has a steeper slope?

What can we conclude from this?

If a slanting plank is used to lift a weight, we have to bear less of the weight and lifting it becomes easier. Such a plank is called an ‘inclined plane’. The more gradual the slope, the lesser is the weight we bear. But such an inclined plane is longer. The steeper the slope, the shorter the inclined plane. But we have to bear a greater weight.

Answer 1

1. Rahi would find the drum heaviest to load because he is not using any plank and has to lift the drum directly.
2. Ravi would find the drum lightest to load because he is using the longer plank A, which has a more gradual slope.
3. Plank A is longer than plank B.
4. Plank B has a steeper slope.
5. A slanting plank makes it easier to lift a heavy object to a height. Such a plank is called an inclined plane. A longer inclined plane with a gradual slope requires less effort, whereas a shorter inclined plane with a steeper slope requires greater effort. Thus, an inclined plane helps us lift heavy objects with less effort.