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: Please help asap - Motion problems

  1. Sep 27, 2004 #1
    Please help asap!!- Motion problems

    I am stuck on these questions, please can some one help asap!!

    1. A ball is thrown horizontally from the top of a building 32.5 m high. The ball strikes the ground at a point 96.9 m from the base of the building. The acceleration of gravity is 9.8 m/s^2. Find the time the ball is in motion. Find the initial velocity of the ball. Find the x and y components of its velocity just before it strikes the ground.

    2. A projectile is fired straight upward at 135 m/s. How fast is it moving at the instant it reaches the top of its trajectory? How fast is it moving at the instant it reaches the top of its trajectory if the particle is fired upward at 33 degrees from the horizontal?
  2. jcsd
  3. Sep 27, 2004 #2
    what have you done?
  4. Sep 27, 2004 #3
    I have no idea what to do in the 1st question because nothing is given except the distance. Can u just tell me what formulas to use? Just a little hint would be helpful.
  5. Sep 28, 2004 #4
    Srry couldnt help you yesturday I had to leave, :mad: . But just seperate it into vertical and horizontal components I think youll be able to do it.
  6. Sep 28, 2004 #5


    User Avatar
    Homework Helper

    1) At the top of the building, what's the only component of velocity?

    2) For the first part, it seems like a 90 degrees angle with the horizontal, so consider what you learnt in 1D motion, Use what you know of projectile motion.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook