If the ball touches the stick and returns, what will happen to the stick? If you say the stick will snatch on the right, you are right. We can think of this as a collision. When the two objects collide, they act for each other. And on each Newton, the forces are equal and opposite, keeping the total motivation of the ball-bat system unchanged. We define the momentum as the product of the mass and velocity of an object.
Since the ball back, the only way to the preserved momentum is to be shocked. .
Collision outside the center
Ok, go get the stick and bring it back to the starting position. The ball was once again released towards the stick. However, this time, it was in the end instead of in the middle. Like this:
The stick is still jerking back to the right, but now it also turn About its center, right? Why does this happen? Well, the motivation is still preserved, but now there are others preserved. The angular momentum is very similar to the simple old momentum except that it is related to rotating motion instead of linear motion.
Although linear momentum depends on the mass and velocity of the object, the angular momentum is equal to the product of the angular velocity of the object and its inertia time. The moment of inertia is similar to the rotating mass, it depends on not only the mass of the object but how the mass is distributed. Therefore, after the bar jerked from the ball impact, it obviously had angle momentum, because it turned.
But what before colliding? The bar does not rotate and has no angular momentum, so the angle momentum is preserved ball Must have angle momentum. Yes, a block may have angle momentum even when it does not rotate. (This is one of the moments when physics seem strange.) The corner moment of the ball depends on its linear momentum And The place where it touches the stick.