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!

Homework Help: Force transfer from compressed spring

  1. Jun 28, 2012 #1
    1. The problem statement, all variables and given/known data
    I have a metal spring 50mm in diameter 152 mm long compressed to half its length ie 76mm by using a weight of 50kg. I have used a clip to hold it compressed. When that clip is broken the spring will expand back to its original length of 152mm. How can I work out how far it will push a tennis ball weighing 1kg into the air and how long will this take ?

    2. Relevant equations
    Newton Acceleration = force/mass
    Speed = distance/time s=d/t
    acceleration= increase in speed over time (speed end -speed beg) / (time end-time beg)

    Please let me know what other equations I should use?

    3. The attempt at a solution
    The tennis ball will accelerate very fast to begin with at rate of 50kg - 1kg but slow as the force of gravity drags it back to the earth
  2. jcsd
  3. Jun 28, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi Neil! Welcome to PF! :wink:

    Use conservation of energy to find when the ball leaves the spring (that'll be when the acceleration = … ?)

    Then use one of the standard constant acceleration equations. :smile:
  4. Jun 28, 2012 #3
    A tennis ball of mass 1 kg? What is inside of it?
  5. Jun 28, 2012 #4


    User Avatar
    Science Advisor
    Homework Helper

    baked beans! :tongue2:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook