1. Not finding help here? Sign up for a free 30min 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!

Acceleration problem 15

  1. Jan 30, 2007 #1
    Problem:
    a rock is thrown vertically with a velocity of 20m/s from the edge of a bridge 42m above the river. how long does the rock stay in the air.

    Equation:
    d=vt+1/2at^2

    Atempt at solution:
    I've actually had a couple of attempts and i came up with a bunch of crazy things. I just need a hint, or to know if im using the correct formula.
     
  2. jcsd
  3. Jan 31, 2007 #2

    cristo

    User Avatar
    Staff Emeritus
    Science Advisor

    Iceclover, please post in the homework forums in future.

    Your equation for this question is correct. Please show your work, and we will be able to help.
     
  4. Jan 31, 2007 #3
    A few good helpful hints is to do this first; label what you have and what you don't have and what you're trying to find. Then look at the equations you have; use algebra to isolate a variable and these types of problems will come a lot more easily.

    Using Y's since this is acting in the Y direction, not the X direction. Also, since it's acting in the Y direction there's a force at work here =). Think about it.

    Y (final position):
    Yo (initial position):
    Vy (final velocity):
    Vyo (initial velocity):
    a (acceleration):
    t (time):

    Hint: Your starting position will usually be 0 m. Unless told otherwise through the problem. Also, you can use a string of equations to solve for things =). Such as isolate the t, and then use that t for another equation =).
     
    Last edited: Jan 31, 2007
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Acceleration problem 15
  1. Acceleration problem (Replies: 14)

  2. Acceleration Problem (Replies: 1)

  3. Acceleration problem (Replies: 4)

Loading...