1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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: Potential Energy and Work done to lift object distance h

  1. May 23, 2013 #1
    Potential Energy and Work done to lift object distance "h"

    The amount of energy needed to power a 0.10 kW bulb for 12 minutes would be sufficient to lift a 1 kg object how high?

    Power = work/time
    PE = mgh

    First I converted kw to watts which is 100 watts. Then converted minutes to seconds = 720 seconds.
    I found the work done by the lightbulb:

    power = work/time
    100 = w/720
    w = 72,000 joules

    Then I plugged that into potential energy(not sure if you can do that), I solved for h using 9.8 for gravity and 1 kg for mass

    PE = mgh

    72,000 = (1)(9.8)h

    h = 7347 meters

    That number seems a bit high
     
  2. jcsd
  3. May 23, 2013 #2

    TSny

    User Avatar
    Homework Helper
    Gold Member
    2017 Award

    That looks good to me.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted