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: Calculating horizontal distance using angle and max height

  1. Sep 23, 2012 #1
    The froghopper, Philaenus spumarius, holds the world record for insect jumps. When leaping at an angle of 58.0 above the horizontal, some of the tiny critters have reached a maximum height of 58.7 above the level ground.

    A)What was the takeoff speed for such a leap?
    I got 4.00 m/s which was correct.

    B)What horizontal distance did the froghopper cover for this world-record leap?
    I really am not even sure how to attempt this.
  2. jcsd
  3. Sep 23, 2012 #2
    Close! The answer should be 40 m/s. Use this form v_y = v_0 * sin(θ). Then, find d from this form:

    v_f² = v_y² + 2ad

    Then, you will need to use this form:

    v_x = v_0 * cos(θ)

    This gives you the time. Now, find the time using this form: v_f = v_y + at [You need to use part (a) to answer this question!] Finally, using the value of v_x and the time you found (given v_y), find the horizontal distance traveled.

    s = v_x * t
  4. Sep 23, 2012 #3
    When I answered 4.00m/s, mastering physics said it was correct.

    I am not sure how to get time, but is v_x=36.7?
    Last edited: Sep 23, 2012
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook