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: Confused know how to do it one way but not the other.

  1. Feb 8, 2009 #1
    1. The problem statement, all variables and given/known data

    when the sun is directly overhead, a hawk dives towards the ground with a constant velocity of 5.00m/s at 60.0 degrees below the horizontal. calculate the speed of its shadow on the level ground.


    2. Relevant equations

    sin rule



    3. The attempt at a solution

    so far i got the ansewr by using 5sin(60) = 2.5m/s

    but there is another way to do this by using the sin rule and i wanted to know how to do it that way too. for the sin rule the solution manual (put sin(90)/(5m/s)) = sin(30)/(Xm/s) i am confused why they use sin(90)/(5m/s) as a ratio with sin(30)/ (Xm/s). why can sin(90)/(5m/s) work as a ratio?
     
  2. jcsd
  3. Feb 8, 2009 #2

    LowlyPion

    User Avatar
    Homework Helper

    I don't think you got the right answer if you used Sin60°.

    60° with the horizontal suggests that the horizontal component of velocity is Cos60° which is the component parallel with the ground.

    Cos60° = Sin30° which may be adding to your confusion.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook