# Question #f81d1

Oct 26, 2014

Bernoulli's Principle can be seen in various places around us.

1. Fast moving train passing the platform
a. When a fast moving train rushes past the train platform, the velocity of the air particles next to the train increases. This leads to a decrease in the air pressure around the train.
b. If one is standing very close to the edge of the platform, they can be harmed as the air will move from the high pressure area behind them to the low pressure area created in front of them by the fast moving train.

2. Spinning of a ball in cricket/baseball/football

Observe the figure carefully.
1. The air travels faster relative to the center of the ball where the periphery of the ball is moving in the same direction as the airflow (left). This reduces the pressure, according to Bernoulli's principle.
2. The pressure increases on the other side of the ball, where the air travels slower relative to the center of the ball (right).
There is therefore an imbalance in the forces, and the ball deflects in the same sense as the spin - from bottom right to top left.