Horizontal veolocity given vertical velocity and angle

[IAmSparticus]

Homework Statement

A person looking out the window of a stationary train notices that raindrops are falling vertically down at a speed of 8.7 m/s relative to the ground. When the train moves at a constant velocity, the raindrops make an angle of θ = 67° when they move past the window as the drawing shows. How fast is the train moving?

Homework Equations

Vx = V0x +axt

The Attempt at a Solution

3.4 and 22.3 m/s are both incorrect.

Couldn't figure out how to do it since clearly you don't just use the Pythagorean Theorem... walk me through it?

 

[tiny-tim]

Hi IAmSparticus!

You'd only use Pythagoras if you wanted the length of the third side.

But you only want the angle … so use cos or sin or tan.