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: Calculating change in momemtum , impulse, and average force of a person in a car.

  1. Feb 27, 2012 #1
    1.A 70 kg front seat passenger is in a car moving initially at 24m/s and is brought to rest by an airbag in 0.4 seconds after a crash.



    2. What is the change of momentum of the person in the car



    3. mΔv = (70kg)(24m/s) = 1680kg m/s

    Am I calculating this right? Is FΔt=mΔv interchangeable depending on the given information?
     
  2. jcsd
  3. Feb 27, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    welcome to pf!

    hi cstatepat! welcome to pf! :wink:
    yes :smile:
    not following you :confused:

    ∫ F dt is impulse

    if F is constant, that's the same as F∆t​
     
  4. Feb 27, 2012 #3
    Re: welcome to pf!

    Thank you for the warm welcome! :biggrin:

    What I am trying to say is if I am trying to calculate the impulse and I look at my equations FΔt or mΔv based on the information the questions gives me I can use either equation to calculate impulse? For example the question I asked didn't have a given for F so therefore I would try to find the impulse using mΔv.
     
  5. Feb 27, 2012 #4

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    oh i see!

    yes, exam questions do that …

    sometimes they give you the data for one side of an equation, sometimes the other side …

    you have to look at what they give you, and work with that! :wink:
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook