(adsbygoogle = window.adsbygoogle || []).push({}); Projectile Motion -- need urgent help :)

If a projectile is fired from the origin of the coordinate system with an initial velocity v and in a direction making an angle alpha with the horizontal, calculate the time required for the projectile to cross a line passing thorugh the origin and making an angle beta less than alpha with the horizontal.

I know that the position of the projectile is described by

y=y0+v0(sin alpha)*t-4.9t^2.

I let the line be y=ax. I also drew a triangle with Beta as the angle, y=ax as the opposite side, and x as the adjacent side. I'm assuming I want to find y in terms of Beta and then set this equal to y in my projectile motion equation...then solve for t???

Thanks in advance!!!

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Projectile Motion - need help

**Physics Forums | Science Articles, Homework Help, Discussion**