more vector physics questions?

Question

A ball is thrown straight upward and returns
to the thrower's hand after 2 s in the air. A
second ball is thrown at an angle of 37 with
the horizontal.
The acceleration of gravity is 9:8 m=s2 :
At what speed must the second ball be
thrown so that it reaches the same height as
the one thrown vertically? Answer in units of
m=s.

Answer 1

The balls must have the same vertical velocity.

The first ball's velocity is described by

vy = voy - gt

where vy is the final velocity in the vertical dimension, voy the initial velocity, g the local acceleration of gravity, and t the elapsed time.

When the ball returns to the thrower's hands, the velocity vy is equal to -voy, so

2 voy = gt or voy = gt / 2

Solve for voy.

The second ball's vertical velocity is v sin 37 so

voy (from the first problem) = v sin 37

Solve for v