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 Motion apple thrown

  1. Oct 21, 2012 #1
    1. The problem statement, all variables and given/known data
    A child sitting in a tree throws an apple core from where he is perched (4 m high) with a velocity of 5 m/s [35 degrees above horizontal] and it hits the ground next to his friend.
    How long before the core hits the ground?

    2. Relevant equations
    dy = vy(initial)t + 1/2at
    quadratic eqn.

    3. The attempt at a solution
    Would I calculate the x-y components of the initial velocity then plug in the initial y velocity to the first aforementioned eqn then solve for t using the latter eqn?
  2. jcsd
  3. Oct 21, 2012 #2
    Don't mind that comment! read it too fast, I did not take angle into account, I thought he was throwing it straight down. Whoops! that's embarrassing, back to high school physics for me
    Last edited: Oct 21, 2012
  4. Oct 21, 2012 #3
    Your first equation is wrong. You're forgetting the dy(initial) term.
    Other than that, you're right.
  5. Oct 21, 2012 #4
    Do not do what FaynmanIsCool wrote. The final velocity is not 0, he didn't account for the launch angle, and he has the wrong sign for a.
  6. Oct 21, 2012 #5
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook