1. Limited time only! Sign up for a free 30min personal 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!

Train question

  1. Mar 25, 2008 #1
    1.A passenger train is travelling at 25m/s around a circular curve of 1000 m radius. if the maximum total acceleration is not to exceed g/10, determine the maximum rate at which the speed may be decreased. Take g = 9.81 m/s^2.

    Answer is 0.756 m/s^2, but what steps do i take to find the answer?
  2. jcsd
  3. Mar 25, 2008 #2
    centripetal acceleration equation and knowing how to add vectors is a good start
  4. Mar 25, 2008 #3
    Wow I actually got this one :)

    You are given the velocity V of the Train (25m/s) and the radius R of the circle (1000m)
    From this you can use the formula Radial Acceleration Arad = V^2 / R to get the Radial Acceleration (That is the acceleration toward the center of the circle to make the velocity change direction)

    Plug those in and you will get Arad = .625

    Now you know that you want the magnitude of total acceleration to be g/10 or .981, and you know one of the components of acceleration, Arad to be .625. Since you know both of these you can solve for the unknown component of accleration which will be tangent to the circle

    Sqrt( .625^2 + A^2 ) = .981

    Do the algebra and you will get the answer to be .756 m/s^2

    hopefully that makes sense.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Train question