Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Simple power problem

  1. Nov 20, 2004 #1
    I am not sure why I am stumped on this problem, but here it is

    An escalator 30.0 meters long slants 30degrees relative to the horizontal. If it moves at 1.00m/s at what rate does it do work in lifting a 50kg man from the bottom to the top?

    Any suggestions on where to start?
  2. jcsd
  3. Nov 20, 2004 #2


    User Avatar
    Science Advisor

    work done in lifting is mgh, so power is time derivative: mg dh/dt. dh/dt is the vertical component of the velocity. Since you have the velocity magnitude and direction, you can figure out the vertical component.
  4. Nov 20, 2004 #3
    What does the d stand for. Do I need to find the height by using sin 30?
  5. Nov 20, 2004 #4
    I have a feeling you don't know calculus. d stands for derivative or change in. your formula for power is P= mgh/t all you have to do is figure out the height using sin30 with your length and your time with sin30 your speed.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook