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: Simple kinematics question i think i am right just need to confirm

  1. Aug 29, 2010 #1
    1. The problem statement, all variables and given/known data
    At t=0 a ball, initially at rest, starts to roll down a ramp with constant acceleration. You notice it moves 1 foot between t=0 seconds and t = 1 second.
    How far does it move between t = 1 second and t = 2 seconds

    2. Relevant equations
    delta x=vit+1/2at2? since it is constant speed wouldn't acceleration be 0?

    3. The attempt at a solution
    it seems like it would be 1 foot right?
    = 1(1)+1/2(0)(1)2
    delta x=1foot?
  2. jcsd
  3. Aug 29, 2010 #2


    User Avatar
    Homework Helper

    No the acceleration would not be zero. If it were zero, then the ball would not move.

    Using this information and the same relevant equations, what is the acceleration? (Remember, initially at rest means no initial velocity)
  4. Aug 29, 2010 #3
    would the acceleration be 1? because it went 1 foot in the elapsed time of 1 sec?

    delta x equals 1/2 foot
    this is wrong. i need a hint please

    or if the time is 2sec the distance would then be 2 foot. but i think that is still wrong
  5. Aug 29, 2010 #4


    User Avatar
    Homework Helper

    Your equation is x=ut+0.5at2 (u= initial velocity)

    Using this equation a≠1 ft/s2.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook