(a) The time taken by the ball to reach its greatest height is 2 seconds.
(b) The time taken by the ball to travel from A to B, C is 4.08 m/s.
(c) The speed with which the ball hits the hoarding is 69.3 m/s.
H = u²sin²θ/2g
H = (40² x (sin 30)²) / (2 x 9.8)
H = 20.4 m
h = ut - ¹/₂gt²
20.4 = (40 x sin 30)t - (0.5)(9.8)t²
20.4 = 20t - 4.9t²
4.9t² - 20t + 20.4 = 0
solve the quadratic equation using formula method;
t = 2 seconds
This is the time of motion of the ball;
T = 2usinθ/g
T = (2 x 40 sin 30)/9.8
T = 4.08 s
v = u + gt
vy = 40 sin30 + (9.8 x 4.08)
vy = 59.98 ms
vx = 40 x cos30
vx = 34.64 m/s
vf = √(vy² + vx²)
vf = √(59.98² + 34.64²)
vf = 69.3 m/s
Thus, the time taken by the ball to reach its greatest height is 2 seconds.
The time taken by the ball to travel from A to B, C is 4.08 m/s.
The speed with which the ball hits the hoarding is 69.3 m/s.
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