Projectile motion

Question

A soccer player kicks a ball with an initial velocity of 8.5 m/s at an angle of 35° above horizontal.

What is the time of flight for the ball? Assume the soccer field is level. 

What is the maximum height the ball reaches? 

Answer 1

v_y = 8.5sin35° - 9.8t;

y = 8.5sin35°t - 4,9t²;

To get time of flight we set y = 8.5sin35°t - 4.9t² = 0; t = 0 (moment of ckick) or t = 8.5sin35°/4.9 = 1.00 sec

At top point v_y = 8.5sin35° - 9.8t = 0 and t = 0.5 sec

So, max height = y(0.5) = 8.5sin35°·0.5 - 4.9·0.5² = 1.213 m