Gravity-Powered LED Lamp

Assumptions:

• The LED bulb used is sixty watts, the same power as an average lightbulb.

Assuming that the average lightbulb needs two 1.5 volt batteries (so three volts total) to run for twelve hours, then in order for a bulb to run for thirty minutes, it would need .0125 volts. Using the equation R = (V^2)/P, R effectively equals 0. That's a little bit of a dead end, so instead, I'm thinking about how 9.8 m/s^2 is the magnitude of gravity. If one newton is the amount of force needed to raise a kilogram one meter against gravity and joules are newtons multiplied by meters, then the question becomes how many joules are needed to power a lightbulb? Well really, since lightbulbs' power is measured in watts and watts are joules per second, then a lightbulb would take sixty joules (at minimum) to be powered. Therefore, one would need sixty newtons to power a sixty watt bulb. This means that sixty kilograms would be needed to power this LED bulb.

This product seems viable because the magnitude of gravity remains constant no matter what, so the rocks would be enough to power the light no matter what the conditions outside. It is also viable because it does not rely on the weather conditions outside functions (unlike turbines or solar panels), so it can work every day throughout the year.