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!

Horsepower moving a mass

  1. Mar 4, 2009 #1
    1. The problem statement, all variables and given/known data
    What minimum horsepower must a motor have to be able to drag a 270 kg box along a level floor at a speed of 1.20 m/s if the coefficient of friction is 0.50?


    2. Relevant equations
    Ffr=mu*mg
    W=Ffr*d


    3. The attempt at a solution
    I ended up having W=Fr*d=mu*m*g*d
    (.5)*(270)*(1.2)*(1.2)=194.4 J/s=.26 hp

    That is way too low.

    Can anyone give me any guidance?
     
  2. jcsd
  3. Mar 4, 2009 #2

    Delphi51

    User Avatar
    Homework Helper

    It looks like you just used 1.2 instead of 9.81 in your calc, but it would be better to use P = F*v.
    If you don't know this formula, it is from P = W/t = F*d/t = F*v.
     
  4. Mar 4, 2009 #3
    Is the way I tried it wrong? I ended up with hp=2.13 and that still seems pretty low
     
  5. Mar 4, 2009 #4

    Delphi51

    User Avatar
    Homework Helper

    That answer looks good!
    Why does it seem low? Picture a pair of horses pulling a sled with a big guy on it at 5 km/hr?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Horsepower moving a mass
  1. Mass on a moving wedge (Replies: 2)

Loading...