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: Constant Acceleration - Kinematics Problem Help!

  1. Nov 20, 2008 #1
    1. The problem statement, all variables and given/known data

    A train at constant acceleration is travelling in a straight line. It passes two points at a velocity of 50km/h and 80km/h respectively. What is the exact velocity of the train when it is halfway between these two points?

    Let v be the exact velocity of the train when it is halfway between these two points

    (Must be solved using two simultaneous equations)

    Thanks! :)

    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Nov 20, 2008 #2

    Kurdt

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    So what have you tried?
     
  4. Nov 20, 2008 #3
    Using formula V^2=(V(0))^2+2*a*s
    where a is acceleration, s is displacement, v is velocity, V(0) is initial velocity:

    80^2=50^2+2as (1)
    M^2=50^2+(1/2)*2*as (2)

    where M is the velocity at halfway

    Solved them simultaneously and got M=5*sqrroot(178)
     
  5. Nov 20, 2008 #4
    You got the right answer...
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook