(ii) a ball is thrown horizontally from the roof of a building 7.5 m tall and lands 9.5 m from the base. what was the ball’s initial speed

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aristocles aristocles · Answer 1 · 2019-06-11T02:29:00+02:00

Answer:

Initial Speed will be 7.68 m/s

Explanation:

Height of the building is given as

H = 7.5 m

now we know that ball is thrown horizontally so here initial speed in vertical direction is ZERO

so we can apply kinematics in vertical direction

[tex]y = v_i t + \frac{1}{2} at^2[/tex]

[tex]7.5 = 0 + \frac{1}{2}(9.8)t^2[/tex]

[tex]t = 1.24 s[/tex]

now the horizontal distance covered by the ball in the same time is

[tex]d = 9.5 m[/tex]

so here we can use equation for uniform motion

[tex]d = vt[/tex]

[tex]9.5 = v\times 1.24[/tex]

[tex]v = 7.68 m/s[/tex]

topeadeniran2 topeadeniran2 · Answer 2 · 2022-06-01T17:20:31+02:00

The initial speed when the ball is thrown horizontally from the roof of a building is 7.68m/s.

From the information given, we firstly need to calculate the time. This will be:

y = ut + 2/2at²

7.5 = 0 + 1/2(9.8)t²

t = 1.24 seconds.

Then, we will use the equation of motion. This will be:

d = vt.

9.5 = v × 1.24

v = 9.5/1.24

v = 7.68m/s

The speed is 7.68m/s.

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