# Raindrops keep falling through my differential equation

Discussion in 'Math' started by Drawoh, Aug 21, 2008.

1. ### Drawoh Thread Starter New Member

Aug 21, 2008
1
0
Greetings,

given a laser beam of 0.5 mm in diameter, hitting a light sensitive target at 10 meters which will register a pulse as small as 1 uSec, what would the differential equation (*) for the number of times per second the beam will be cut during a normal rainstorm?

*) I assume it would be a diff.eq, but am near clueless how to approach this.

"Raindrops range from 1/100 inch (.0254 centimeter) to 1/4 inch (.635 centimeter) in diameter... Not including wind-driven rain, raindrops fall between 7 and 18 miles per hour (3 and 8 meters per second) in still air. The range in speed depends on the the size of the raindrop. Air friction breaks up raindrops when they exceed 18 miles per hour. "

thanks much for any suggestions,
Howard
________________________________
references:
http://www.weatherwizkids.com/Rain.htm
http://ga.water.usgs.gov/edu/raindropshape.html

2. ### thingmaker3 Retired Moderator

May 16, 2005
5,073
8
Why would it be a differential equation? Wouldn't one just use drops per square meter per second and plug into an algebraic expression?