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: Help With *Simple* Projectile Motion Problems!

  1. Oct 21, 2008 #1
    1. You accidentally throw your car keys horizontally at 5.0 m/s from a cliff 78 m high. How far from the base of the cliff should you look for the keys?

    2. Maxiumu Horizontal Distance
    Range = [Vi^2]/2 x (2sinTcosT)(G)

    I know that it's a very simple problem, but I need help getting the steps down. I believe that the above formula is correct, but I could be wrong. If the above formula is correct, then how would I find the measurment of angle "T"?

  2. jcsd
  3. Oct 21, 2008 #2
    I think you are making it too complicated.

    Write out your variables:

    initial velocity:
    final velocity:

    based on the variables you have, you should be able to use a distance formula.
    I am unsure which variable you are using right now...

    Hope this helps.
  4. Oct 21, 2008 #3

    Well, it's a bit too late, I just submitted my final (and incorrect) answer to WebAssign. But here's what I know so far:

    initial velocity: 5.0m/s
    final velocity: (I believe it is irrelevant to the problem at hand.)
    distance: (X)
    time: (?) Unsure how to solve for time in this case.
    acceleration: 9.8m/s (Gravity)

    My teacher is a great guy, but he recently emigrated from Pakistan and has a very thick accent, which makes it difficult to understand him. I'm sure he instructed us to do solve the problems correctly, but I didn't come away with much on this subject.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook