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!

Projectile Motion Problem Help

  1. Sep 24, 2012 #1
    I am in an Honors Physics I class at my school and we are just starting to learn about projectile motion. I am having a bit of trouble with some homework and am in need of help.

    Problems:
    1. I kick a rock horizontally off a ledge that is 20 m high. Once in the air, the rock is in free-fall. How far forward does the rock travel before hitting the ground?
    A: I used ΔY=1/2(a)(Δt)^2 to solve for Δt if ΔY = 20m Vy,i = 0 m/s and
    a = -9.8 m/s2. I got Δt ≈ 2.0s. Is it even possible to solve this with the given information?

    2. A long-jumper leaves the ground with an initial velocity of 12 m/s at an angle of 28 degrees above the horizontal. Determine the long-jumper's time of flight.
    I solved for the y component using Vy,i = Rsinθ and
    Vx = Rcosθ. Vy,i = 5.6 m/s and Vx = 10.6 m/s. a = -9.8 m/s^2 but that was as far as I could get with the given information.
     
  2. jcsd
  3. Sep 24, 2012 #2
    1. Just a nudge, it won't go far forward. Forward depends on initial horizontal velocity.
    2. Hidden data. Vertical displacement =0
     
  4. Sep 24, 2012 #3
    The problem is that the initial horizontal velocity is not given neither is the horizontal displacement. The time was calulated base upon other given factors.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Projectile Motion Problem Help
Loading...