# Homework Help: Energy when going down the escalator

1. Nov 17, 2012

### dawn_pingpong

1. The problem statement, all variables and given/known data

Hello, I was just thinking about this when going down the escalator today... When one goes down the escalator, one loses potential energy, and work is done by the escalator to bring you down. In a sense, energy is lost from the escalator too (as it does work). Taking that the escalator speed remains constant throughout the ride, where has your gravitational potential energy go to?

Yes, in a sense, when one portion of the escalator moves down (the front exposed part), another part is transported back to the surface through the space underneath the escalator. However, as the front part goes down, the bottom (which is supposedly of equivalent mass etc, as it is a roller) moves upwards, which should perfectly balance itself, which means all of your potential energy were transformed to heat and sound etc? But this really doesn't seem right...

2. Relevant equations

3. The attempt at a solution

2. Nov 17, 2012

### voko

Try to consider two situations: the load is less than or just enough to let the escalator "free wheel" (i.e., work with zero electric input) and the load is greater than that.