Question

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Answer 1

Data Given
Initial Speed U = 80 ft/s
Acceleration due to gravity g = -32.2 ft/s^{2}
When it reaches at maximum height its velocity becomes zero, So using first equation of motion,
\[v = u + at\]
\[0 = 80 ft/s -32.2 ft/s^{2} \times t\]
\[t = \frac{ -80 ft/s }{ -32.2 ft/s^{2}} = 2.4845 s\]
This is the time taken by ball to reach maximum height, same time it will take to return back. So total time taken by the ball to return to same point
\[T = 2.t = 2\times2.4845 s = 4.969 s \approx 5 s\]