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: Projectile Problem - Time of Peak

  1. Nov 29, 2006 #1
    If a fireworks rocket has an initial upward speed of 58 m/s when launched, for how long will it coast before reaching its peak?

    So could I use the equation t=v0z/g?

    When I use this I get the peak to be 5.9s. Is v0z = 58 m/s or would that be 0? Am I approaching this correctly?
  2. jcsd
  3. Nov 29, 2006 #2
    Anyone have an idea?
  4. Nov 29, 2006 #3
    well you need an angle because time would depend on the angle you use. For example if you launched the rocket at a 50 degree angle the time to reach its peak would be 58sin50 / 9.81 = 4.42 secs. But if you launched the rocket at a 70 degree angle it would be 58sin70 / 9.81 = 5.55 seconds. So you would have to specify the angle.
  5. Nov 29, 2006 #4
    oh ok, so even if you shoot the firework straight up, it still needs an angle?
  6. Nov 29, 2006 #5
    well straight up it would be 90 degrees. 58sin 90 / 9.81 = 5.912 seconds.
  7. Nov 29, 2006 #6


    User Avatar
    Staff Emeritus
    Science Advisor

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook