1. Not finding help here? Sign up for a free 30min 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!

Checking my answers

  1. Oct 27, 2009 #1
    1. The problem statement, all variables and given/known data
    A washing machine that weighs 1400N must be put into a delivery truck bed that is 1.2 m off the ground. A worker uses a force of 450N to push the machine up a ramp that is 4.3m long. What is the efficiency of the inclined plane?


    2. Relevant equations
    e=(MA/IMA)100---- efficiency of a machien in % is = to its mechanical advantage, divided by the ideal mechanical advantage, multiplied by 100.
    MA=Fr/Fe---- mechanical advantage=the resistance of force divided by the effort force.
    IMA=De/Dr----the ideal mechanical advantage of an ideal machien is=to the displacement of the effort force, divided by the displacement of the load.


    3. The attempt at a solution
    MA=1400N/450N=3.11N, I think i did that part right.
    IMA=1.2m/4.3m=0.28m, I think i did this part wrong.
    e=(3.11N/0.28m)100=1110.71joules.
     
    Last edited: Oct 27, 2009
  2. jcsd
  3. Oct 27, 2009 #2

    rl.bhat

    User Avatar
    Homework Helper

    Hi Jonathan Teas, welcome to PF.
    First of all MA or IMA are pure numbers. No units for them.
    Next IMA = Distance traveled by effort/ distance traveled load. = ...?
    In Ist or second type of machine IMA cannot be less than one.
     
  4. Oct 27, 2009 #3
    If IMA= Distance traveled by effort/ distance traveled load
    then IMA= 4.3m/1.2m=3.58 then no unit?
    so the answer is 3.11no unit again/3.58=(0.87)100=87%
    Thank you very much.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Checking my answers
  1. Pls check my answer (Replies: 3)

  2. Check my answer please (Replies: 1)

Loading...