Principles of Projectile Motion

 

 

Have you ever been sitting at rest at a light with a bus in the lane next to you?  When the bus starts to move forward, you will often perceive for a moment that you are moving backwards.  The same can happen when two trains are side by side.  If it were not for other objects around you, it might be difficult to determine who was moving and who was standing still.

Now think about this: If a boy were standing on a moving train and dropped his book, what would the path of the book look like to the boy on the train?  What would the path look like to someone standing on the train platform watching the train pass?