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: Need help finding the relationship between force and acceleration

  1. Sep 29, 2010 #1
    1. The problem statement, all variables and given/known data

    A force is applied that makes an object move with the acceleration shown below. Assuming that friction is negligible, sketch a force-time graph of the force on the object on the axes below.

    Since i don't have a scanner. Let me describe the graph of the acceleration. It oscillates from positive 1 to negative 1.5, then to positive two, then negative 1.5 then to positive 1 and evens out. So there are three humps within 5 seconds.

    i don't know the relationship between the acceleration graph and force graph so i am stuck here. I know that they have to be in the same direction because 'a force [was] applied that made the object move'. But how will the graph of the force vs time look. Will it just be the derivative of the acceleration graph?
     
  2. jcsd
  3. Sep 29, 2010 #2
    I may be wrong here, but I think Newton came up with a famous equation that relates force to acceleration.
     
  4. Sep 29, 2010 #3
    well i was looking more for "the accleration is the slope of the velocity graph" but in regards to force and accleration.

    another example would be the velocity is the slope of the position graph.

    so, if i may add another question: what is the force graph in relation to the acceleration graph. if the velocity graph and acclertaion graph are both constant, that is that they are both horizontal lines; what will the force graph look like?
     
  5. Sep 29, 2010 #4
    if the velocity is constant, than acc. and force are zero.

    Another thing - the graph of force and acceleration (with respect to a common variable, say time) basically have the SAME shape (f=ma, m being a scalar).
    Absolute values will change according to the value of mass in the equation above.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook