If a professional jumper jumps in a running trainn and remains in air (say,4 ~5 sec),does he returns back his original position?
To determine whether a professional jumper, who jumps in a running train and remains in the air for 4-5 seconds, will return to their original position, we need to consider a few factors:
1. Initial velocity: The speed at which the train is moving when the person jumps.
2. Jumper's takeoff velocity: The velocity with which the jumper leaves the train while jumping.
3. Gravity: The downward force acting on the jumper due to gravity.
If the jumper jumps vertically relative to the train (meaning they do not have any horizontal velocity), they will essentially follow a projectile motion.
During the time the jumper remains in the air, they will experience the influence of gravity, which will cause them to fall downward. However, since the train is also moving forward, the horizontal position of the jumper will change while they are in the air.
Whether the jumper returns to their original position depends on the relative velocities of the jumper and the train. If the jumper's horizontal velocity matches that of the train, their horizontal position will not change, and they will indeed return to their original position in the train.
However, if the jumper has a different horizontal velocity than the train, their horizontal position will change, and they will not return to their original position.
In summary, if the jumper jumps vertically relative to the train and their horizontal velocity matches that of the train, they will return to their original position.