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!

Finding the distance with an acclerometer and a timer

  1. Apr 12, 2010 #1
    1. The problem statement, all variables and given/known data

    An accelerometer measures the acceleration of an object every 0.050s.
    The initial velocity is 0 m/s.
    The initial distance is 0 m/s.

    The accelerations at the times (in m/s^2):
    a(0.000) = 5
    a(0.050) = 7
    a(0.100) = 10
    a(0.150) = 15
    a(0.200) = 15
    a(0.250) = 15
    a(0.300) = 5
    a(0.350)= -10
    a(0.400)= -10

    If possible, estimate the distance traveled by the object from t=0s to t=0.400s.

    2. Relevant equations
    [tex]
    v_{ave} = \Delta x / \Delta t
    [/tex]

    [tex]
    a_{ave} = \Delta v / \Delta t
    [/tex]

    [tex]
    x = x_0 + v_0 t + (1/2) a t^2
    [/tex]

    [tex]
    v^2 = v_0^2 + 2 a \Delta x
    [/tex]


    3. The attempt at a solution

    I tried to find the slopes of the a(t) graph by having v(.025)=(7-5)/(.05-0) and v(.075)=(10-7)/(.1-.05). Then I tried to find the slope of the v(t) graph by x(.05)=(v(.075)-v(.025))/(.075-.025)=400m which is, of course, extremely high for the times and accelerations.

    Another approach I thought of was to add up all of the recorded accelerations, divide them by the number of accelerations found, and use this average acceleration in

    [tex]
    x = x_0 + v_0 t + (1/2) a t^2
    [/tex]

    as

    [tex]
    x = 0 + 0 + (1/2) (average acceleration) (total time)^2
    [/tex]

    Are these correct approaches? Are there any other ways to do this that are more accurate?

    Thanks.
     
  2. jcsd
  3. Apr 13, 2010 #2
    You have to calculate the speed after every step

    calculate the average acceleration in the first time interval.
    use v = v_0 + a t to get the speed at the end of the first time interval
    calculate the average speed in the first time interval
    use x = x_0 + v_avg * t to get the position at the end of the first time interval

    then repeat these steps for the next 7 time intervals
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Finding the distance with an acclerometer and a timer
  1. Find the distance (Replies: 2)

  2. Find Distance. (Replies: 2)

  3. Finding Distance (Replies: 10)

  4. Finding the Distance (Replies: 1)

  5. Find the distance (Replies: 1)

Loading...