can you please help me with this question thank you

Question

A cannon fires a cannonball at an angle of 20 and gives it an initial velocity of 100m/s.



A) How far horizontally does the ball land?

B) How high does the ball reach?

Answer 1

x = 100cos20°t, y = 100sin20°t - 4.9t²;

v_x = 100cos20°, v_y = 100sin20° - 9.8t.

A) When ball land y = 0; 100sin20°t - 4.9t² = 0, t = 0(moment of start), t = 100sin20°/4.9 = 6.98 s

then horizontal distance x = 100cos20°·6.98 = 655.91 m

B) At top point v_y = 0, or 100sin20° - 9.8t. = 0, t = 100sin20°/9.8 = 3.49 s

Now maximum height ball reach y_max = 100sin20°·3.49 - 4.9·3.49² = 59.68 m