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: Incline problem

  1. Nov 26, 2008 #1
    Two packages at UPS start sliding down the 20 degree ramp.Package A has a mass of 5.0kg and a coefficient of friction of 0.20. Package B has a mass of 10 kg and a coefficient of 0.15. how long does it take package A to reach the bottom?

  2. jcsd
  3. Nov 26, 2008 #2
    The question isn't very clear; does package B push on package A and help it accelerate?
  4. Dec 4, 2008 #3
    that's all i'm given...
  5. Dec 4, 2008 #4
    tan(20) =0.36 > 0.2, so the sliding that just started will continue.
    So resolve the mass into a normal and a downward (along the slide) component.
    Subtract the frictional force will give you the downward force.
    Dividing the force by the mass gives the acceleration.
    Use the usual formulae for acceleration as a function of distance and speed to find the time required to travel the down ramp of length L.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook