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: Romeo and juliet

  1. Jan 22, 2007 #1
    Romeo tosses a pebble at Juliet's window to wake her. Unfortunately, he throws too large a pebble too fast. Just before crashing through the glass, the pebble is moving horizontally, having traveled a horizontal distance x and a vertical distance y as a projectile.

    Find the magnitude of the pebble's velocity as it leaves Romeo's hand.

    Find the direction of the pebble's velocity (angle above the horizontal) as it leaves Romeo's hand.

    The answers need to be expressed in x y and g.

    Any ideas?
  2. jcsd
  3. Jan 22, 2007 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    This looks like a homework question. PF rules state that we must see your work before we can help you. So, do you have any ideas?

    P.S. In future please post such questions in the homework forum.
  4. Jan 22, 2007 #3


    User Avatar
    Gold Member

    Do you have any ideas? Tell us what you have done. Also it would help to draw a diagram. Since it wants the direction, you'll need to use a right triangle somewhere in your diagram.

    EDIT: aw cream cheese. It took me two minutes to type this :)
  5. Jan 22, 2007 #4
    I thought it was, Vo = sqrt[((x/t)^2)+(((y-gt^2)/t)^2)] for the magnitude, but the solution does not depend on "t".
  6. Jan 22, 2007 #5
    does "moving horizontally" mean that the final velocity in the y direction is 0?
  7. May 12, 2008 #6
    @ bcotten. I'm a total noob at this, but I'm going to guess that moving horizontally means that the pebble is at the apex of the projectile motion. I'm guessing that the time = v(initial)/g.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook