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: Newton's 2nd law

  1. Sep 19, 2005 #1
    I figured out the horizontal friction force, Fpx to be 55.11 N and the normal force exerted vertically to be 190.8 N. And the other info given is F = 84 the lawn mower has a mass of 13 kg and moves at a constant speed. The lawn mower is at an angle of 49 degrees to the horizontal. I need to determine the force the person must exert on the lawn mower to accelerate it from rest to 1.3 m/s in 2.0 seconds (assuming the same retarding force).
    Do I use the equation 84 cos 49 + F (friciton) = ma??? Or how do I set up this problem?
     
  2. jcsd
  3. Sep 19, 2005 #2

    lightgrav

    User Avatar
    Homework Helper

    If the person's Force is along a 49 degree handle
    (while the lawn mower itself is on level?)
    the person's force will increase the N required,
    and might increase the friction Force.

    Does your friction stay at 84 cos(49) ?
    then get Fx_extra = ma_x
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook