Using a money vortex to collect coins | Hey Ray
PITTSBURGH (KDKA) - You may have seen what is called a money vortex before. These are a type of bank that have a fun way to deposit money. You drop in a coin, and it spins down the funnel, picking up speed and tilting more and more as it moves lower in the funnel.
You will notice that the coins do not tip over, and that is because the physics behind how this works are pretty cool.
First, the money has to be rolling. If you just set a piece of change on the edge, it will just slide in. Kind of boring. So we know that there has to be some motion to the money to make it work. At some point, you would think the coin would tip over and just fall into the bottom, but there are more forces than just gravity at work.
According to the University of California Santa Barbara, When the coin rolls down the ramp, it acquires a tangential velocity causing the coin to travel in circles around the funnel. Tangential velocity is the linear speed of an object moving along a circular path, this linear speed is always at a right angle, or tangent, to the radius of the circle. Simply, it is a force that helps the coins move in a circular path around the funnel.
Since the coin is spinning it also has angular momentum. You may remember that from when we talked about gyroscopes. This is a physical property that essentially prevents a change to its orientation unless it is acted upon by an external force. That is why the coin doesn't fall over!
The velocity increases as the radius of the funnel gets smaller, so as gravity pulls the coin's circular path down the funnel, the coin starts to spin around a lot faster. This is why the coins are the fastest in the smallest part of the funnel.
