What will happen when you throw a ball in a moving bus?
Why a ball thrown straight up inside a moving bus lands back in your hand, and why the same throw from an open truck does not.
Suppose you are on a running bus and you have a tennis ball in your hand. You throw it up in the air. What will happen? Will it return back to you, or will it go far beyond you because you are in a running bus?
Generally, if you were standing in a static position relative to the world, and if you threw the ball straight up to the sky, then the ball would come back exactly to you. However, the case is not the same when you are in a running vehicle. That time you are moving from one place to another. Therefore, you think that after throwing the ball, the ball will fall down far beyond you, because in the meantime you have traveled far from your previous position, while the ball has fallen to the position from where you threw it.
This is a misconception. The truth is the ball will come exactly to you, whether you are in a running bus or standing on the road. I will tell you why.
For example, imagine your bus was going at a speed of 5 meters per second. You throw the ball up and it stayed 2 seconds in the air. So, in these 2 seconds, you have moved forward 2 × 5 = 10 meters. However, as the ball was in the air, it was supposed to be in the place from where you threw it: 10 meters behind. But the thing is, when you threw the ball you were not in a static position. You and your hand had a speed of 5 m/s, like the bus. So the ball had two speeds in two different directions: 5 m/s toward the direction your bus was moving, and toward the sky at the speed of throwing the ball upward. When anything has two directions, it will behave like a projectile.
As a result, when you were moving forward at a speed of 5 m/s, the ball was also moving at that speed in the air, as well as moving upward and then downward with the speed you threw it. But it is not perceivable normally. That’s why the ball will fall to you.
However, the case is not the same when you are throwing a ball from an open truck, or from a bus where the windows are open. This is because the force of air will play a significant role in impeding the ball from moving forward. That’s why if you throw a ball from an open moving truck, the ball will never come back to you.
The good thing about science is that it’s true, whether or not you believe in it.