Question

Why do the calender papers move forward when we put on a fan ?​

Answer 1

Explanation:

According to the principal of aerodynamics, when air moves at a faster speed the pressure of air at that side decreases while it increases on the other side.

Airplanes fly on the same principal, when pressure on the higher side of wings decreases and increases on the lower side due to which it is lifted.

Same happens to the papers. When air is blown on the front side, pressure on the other side is increases due to which they move forward.

Answer 2

Why do the calender papers move forward when we put on a fan ?​

The above phenomena can be explained by Bernouli's Principle.

• " When air moves fast parallel to the top surafce of any body pressure of the air above the surface is lesser than pressure below that surface. This is called Bernouli's Principe.

• When the ceiling fan rotates with high speed the air is circulated with high speed and its direction would be parallel  to the plane of the wall and calender.

• So a low pressure region is created infront of the calender and hence it moves towards the air flow and away from the wall.