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!

1D Kinematics

  1. Sep 27, 2011 #1
    1. The problem statement, all variables and given/known data
    A car is initial at rest. It accelerates over a distance of 1250m and reaches a speed of 112 km/h. Find: A) the acceleration for the car B) the time it took for it to reach this final speed C) the average speed

    2. Relevant equations
    A = delta V/ delta T or v^2 = V (initial)^2 + 2a (d -d(initial))
    d = d(initial) + vt

    3. The attempt at a solution
    1250 = 0 + 31.1(t)
    t = 40.18

    A = 31.1/40.18
    A = .77 m/s^2

    BUT here is the problem

    if i use v^2 = V (initial)^2 + 2a (d -d(initial))
    31.1^2 = 0^2 + 2a(1250)
    A = .387 m/s^2
    that is half of the first one?

    that is where i need help
  2. jcsd
  3. Sep 27, 2011 #2
    Your solution for the acceleration in this section is correct.

    Remember, the car is accelerating over this distance. It travels the 1250 meters before it reaches it's final speed.

    Do you have the other equations of motion there? Which of them can you use that uses time and acceleration to compute a distance?
  4. Sep 27, 2011 #3
    Not sure. Can you please explain?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: 1D Kinematics
  1. 1D kinematics (Replies: 1)

  2. 1D Kinematics (Replies: 5)

  3. 1D kinematics (Replies: 2)

  4. Kinematics in 1D (Replies: 2)

  5. 1D Kinematics (Replies: 10)