# Physics of a falling raindrop

1. Nov 17, 2007

### hollistb

So i have a problem with a question in which there is a falling raindrop where the mass and the radius are proportional and i have to find the acceleration with respect to radius and velocity.. I figured that bc it was falling its acceleration would be equal to g... but that seems to easy!!!

2. Nov 17, 2007

### Vazier

the thing to be considered may be the drag of the drop as it falls down which depends on the surface area of the rain drop. this drag limits the velocity of the drop to a specific number.....

3. Nov 21, 2007

### tedjan

This is a very old problem. Unfortunately, I remember the answer, g/7, but I don't remember how you get it. It has an unusual solution. There a special substitution that you need to make for the mass, otherwise the problem is insoluble. You might try to research "raindrop problem" with Google.

4. Nov 21, 2007

### stewartcs

Sounds right to me, the only force accelerating a rain drop is due to gravity.

The terminal velocity however depends on the mass and radius.

http://en.wikipedia.org/wiki/Terminal_velocity

Maybe you're supposed to show the relationship between g (the rain drop's acceleration) and the terminal velocity of it.