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

[camboguy]

Homework Statement

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.

Homework Equations

sin rule

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?

 

[LowlyPion]

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.