# Help my noodle- Falling weight and driveshaft problem

1. Jan 26, 2007

### silverfish

Hi folks,

Am clueless in the area of physical / mechanical engineering, but I need to get an idea of how to calculate the following problem, can someone guide me to the necessary formulas needed to calculate the following problem

Assume there is a weighted cylinder suspended by a drive cable which is wound around a drive shaft. Known factors are the weight of the cylinder, weight and diameter of driveshaft, total weight of drive cable, total length of cable wrapped around the driveshaft and starting distance between the driveshaft and cylinder. Ignoring aerodynamic / friction / Heat Issues, just broadly calculated and starting from a static point, once the cylinder is released to fall thus turning the shaft

How do I calculate

1) How much energy would the drive shaft produce at a given distance of travel by the cylinder ?

2) What would the rotational speed of the driveshaft be at a given distance
of travel by the cylinder ?

3) Am I correct in assuming (though I know what assumption does) that there is an optimal fall distance whereby the cylinder has reached its maximum potential to deliver power to the driveshaft.

Cheers