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A is dropped from the top of a building and hits the ground in 10 seconds. Another ball B is thrown straight down from the same building one second after dropping ball A. Neglect air resistance and consider g - 9.8 m/s2 . What should be the initial velocity of ball B so that it hits the ground simultaneously with ball A: Select one: O a. 9.8 m/s b. 20.6 m/s c. 4.3 m/s d. 10.3 m/s

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ch3ng27

Answer:

D. 10.3 m/s

Explanation:

A:

u = 0 m/s

a = 9.8 m/s²

t = 10 s

Using

[tex]s = ut + \frac{1}{2} a {t}^{2} \\ s = \frac{1}{2} (9.8) {(10)}^{2} \\ s = 490m[/tex]

B:

Since B is thrown one second after dropping A, B must take 9 seconds to reach the ground simultaneously with A.

s = 490m

a = 9.8 m/s²

t = 9s

Using

[tex]s = ut + \frac{1}{2} a {t}^{2} \\ u = 10.3m {s}^{ - 1} [/tex]

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