How Do You Calculate Initial Speed in Projectile Motion Problems?

[heeling23]

1. A ball is thrown horizontally from a height of 22 m and hits the ground with a speed that is three times its initial speed. What was the initial speed?

2. A projectile is fired with initial speed v at an angle 30° above the horizontal from a height of 41 m above the ground. The projectile strikes the ground with a speed of 1.4v. Find v.

These are essentially the same problems right? Except for the fact that #2 has a vertical initial velocity. I tried using V^2=Vo^2+2ah but I got the answer wrong. Then I tried finding the time for the first one using y=1/2at^2 and then using v=vo+at and I got the wrong answer again.

Any help is appreciated!
Thanks,
heeling23

 

[Doc Al]

I tried using V^2=Vo^2+2ah but I got the answer wrong. Then I tried finding the time for the first one using y=1/2at^2 and then using v=vo+at and I got the wrong answer again.

Either approach, done correctly, would work. Post the details of what you did for more help. (Hint: Only the vertical component of motion is accelerated.)