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: Momentum and vector help

  1. Oct 17, 2004 #1
    i know that the formula for impulse is f(delta)t. my question ask " a truck with a mass of 1.20 x 10^3 kg has its brakes applied for 5.50s as it slows down from 24.0m/s, west to 10.4m/s west. determine the magnitude and direction of the impulse provided by the brakes." i know you need to use the formula
    f(delta)t = m(delta)(vf-vi). but since i want the impulse do i just fill in the right side of the formula and git impulse or do i use the time also. thanks.
     
  2. jcsd
  3. Oct 17, 2004 #2
    u can safely ignore "time=5.50s" as impulse is independant of time.


    just impulse= (1.20 x 10^3)(24.0-10.4)
     
  4. Oct 17, 2004 #3

    robphy

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The impulse is the left-hand-side: (Favg)(Delta t).
    By the impulse-momentum theorem, it then follows that it is equal to the change-in-momentum.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook