Find the Launch Speed for a 20m High Projectile

[voygehr]

Homework Statement

The maximum height reached by a projectile is 20 m. The direction of the velocity 1.0 s after launch is 20°. Find the speed of launch.

Homework Equations

vertical component of velocity = $$u \sin\theta - gt$$
horizontal component of velocity = $$u\cos\theta$$
where theta is the launch angle

The Attempt at a Solution

I made several attempts to solve this but I can't seem to figure it out. Are we presented with enough information?

 

[tiny-tim]

welcome to pf!

hi voygehr! welcome to pf!

(have a theta: θ )

find v_y0 first …

show us what you get ​

 

[voygehr]

just solved it!

v=34 m/s at 36°

thanks anyway! (do I delete this thread now?)

 

[tiny-tim]

no, it remains for ever as a triumph of human perseverance and ingenuity!

 

[voygehr]

haha excellent!