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!

Does mass affect acceleration on a slope?

  1. Mar 18, 2015 #1
    1. The problem statement, all variables and given/known data
    A cart goes down a ramp with an incline of 10 degrees with acceleration A. Would adding mass on that cart change the acceleration?

    2. Relevant equations
    F = ma

    3. The attempt at a solution
    so I tested this in lab and no, the added weight didn't affect the acceleration of the cart. It went down at the same rate. How can I mathematically prove this?

    I remember an experiment where a feather and a marble dropped at the same rate inside a vacuum so mass didn't affect acceleration in that case.
     
  2. jcsd
  3. Mar 18, 2015 #2

    Orodruin

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Did you try applying Newton's second law?
     
  4. Mar 18, 2015 #3

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    You cannot prove an empirical truth mathematically.

    But you can use F=ma to find that the acceleration predicted by Newton's Law is consistent with observation.
    You can also reason by logic that it makes sense.

    The most famous version of the feather drop demonstration was done on the Moon:
     
  5. Mar 18, 2015 #4
    how would you apply F=ma in this situation?

    if a was the same for both (with and without the added weight)
    then m should be proportional to F

    but what is F in that case?
     
  6. Mar 18, 2015 #5

    Orodruin

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    This is whatyou have to model. What forces are acting and what are their directions and magnitude?
     
  7. Mar 18, 2015 #6
    we have friction and Fg x. and Fnormal. is that correct?
     
  8. Mar 18, 2015 #7

    Orodruin

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    So how does gravitational force, the normal force, and friction force depend on the mass?
     
  9. Mar 18, 2015 #8
    gravitational force = m g

    normal = m g

    frictional force= coefficient of friction x Fnormal
     
  10. Mar 18, 2015 #9

    NascentOxygen

    User Avatar

    Staff: Mentor

    You haven't drawn the diagram, have you, showing a mass sliding down a slope?
     
  11. Mar 18, 2015 #10
    udSFB02.png

    oops, Fnormal = Fg y

    Fgx is the acceleration of which it goes down the ramp.

    F g x = sin theta x Fg

    F g y = cos theta x Fg
     
    Last edited: Mar 18, 2015
  12. Mar 18, 2015 #11

    Orodruin

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    So since all of the forces are proportional to the mass, what can you say about the acceleration through Newton's second law?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted