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: Finding Acceleration in f=ma

  1. Jan 24, 2012 #1
    1. The problem statement, all variables and given/known data

    The fastest served tennis ball, served by "Big Bill" Tilden in 1931, was measured at 73.14 m/s. The mass of a tennis ball is 57.0 g, and the ball is typically in contact with the tennis racquet for 30.0 {\rm ms}, with the ball starting from rest.

    2. Relevant equations

    F=ma
    p=mv (?)
    don't understand how to find the acceleration

    3. The attempt at a solution

    f=57(a)

    found the momentum in an attempt to relate it to acceleration, but I failed. Any ideas on how to find the acceleration?
     
  2. jcsd
  3. Jan 24, 2012 #2

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    What's the definition of acceleration?
     
  4. Jan 24, 2012 #3

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Hello trynagetby. Welcome to PF.

    The ball goes from zero to 73.14 m/s in 30 milliseconds. What's the average acceleration ?
     
  5. Jan 25, 2012 #4
    so it should be this

    a=(Vf-Vo)/t

    30 milliseconds = .03 seconds

    73.14/.03 seconds

    = 24380 ?

    57(24380) = 1389660 but my online homework is telling me thats wrong
     
  6. Jan 25, 2012 #5
    put your units in your calculations and you'll see the problem.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook