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: Spring and Projectile Motion Problem

  1. Nov 24, 2004 #1
    Ok, I need some help getting started with a problem involving a spring and projectile motion.

    A picture of the problem is attached.

    Part A was easy, done with projectile motion. I worked it out to time = sqrt((-2h)/g).

    Now I'm stuck on where to start with part B because we are not given a spring constant. I know that just the speed as it leaves the platform needs to be found because there is no acceleration on the x component.

    I played around with simple harmonic motion equations but keep getting stuck on the fact that I dont know what K is or the force needed.

    And for reference I'm in ap physics b.

    Any help to get me started would be greatly appreciated.

  2. jcsd
  3. Nov 24, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Hint: You figured out the time in part a. What horizontal distance did it travel in that time?
  4. Nov 24, 2004 #3

    Thanks. It was so obvious, I got too caught up in the equations. I never thought I would forget that v=s/t but I just did...Thanks for the reminder.

    So I got v=D/sqrt((-2h)/g)

    Ok, so then It's a matter of using an equation for velocity of a spring, v=(2piX)/T and combining it with T=2pisqrt(m/k), I can find K [got part D done right there!] and then using w= 1/2kx^2.

    Sounds good to me.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook