A stone is thrown upwards from the top of a 59.4 m high cliff with an upward velocity component of 19.6 m/s. How long does it stay in the air?
Correct answer A. 6.00 s
Explanation
Taking upwards as positive, -59.4 = 19.6t - 4.9t², which gives t² - 4t - 12.1 = 0 and a positive root of about 6.0 s.
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