Question

Safawi kicked a ball with an initial speed of 20 ms) at 30° angle. If the ball experienced a constant vertical acceleration of -9.81 ms?, calculate the ball's maximum height and distance. Explain how soccer player could apply the force of summation theory to optimize his kicks performance.
(10 marks)​

Answer 1

Answer:

maximum height = 5.1 m  distance traveled/horizontal displacement = 35.3m

Explanation:

Vy = sin 30º • 20 m/s

Vy = 10 m/s

Vx = cos 30º • 20m/s

Vx = 17.3

V final = V initial + acceleration • time

0 = 10m/s + (-9.81 m/s/s) • time

subtract 10 m/s from both sides

-10m/s = -9.81m/s/s • time

divide each side by -9.81m/s/s

t = 10/9.81 s or roughly 1.02 second  

the time to reach max height is equal to 1.02 s

Height = 1/2 • acceleration • time^2  + Vy • time

Height = 1/2 • (-9.81 m/s/s) •  1.02s^2  + 10m/s • 1.02 s

Height = 5.1 m

the maximum height of the ball is equal to 5.1m

since the ball starts from an initial height of zero and has a final height of 0 once it reaches the ground, the time needed to reach max height is the same amount of time to fall back down to earth. thus, time total is equal to 1.02s multiplied by 2

t total = 1.02s • 2

t total = 2.04s

horizontal displacement = Vx • time total

horizontal displacement = 17.3m/s • 2.04 s

Horizontal displacement = 35.3m