Acheerleaderfellofffromaheight12feetabovethegroundbeforeshewascaughtbyherteammatesfrombelow.\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05(a)Howlong(inseconds)didshefallassumingthat12feetisthe

Question

A cheerleader fell off from a height 12 feet above the ground before she
was caught by her teammates from below.
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(a) How long (in seconds) did she fall assuming that 12 feet is the total distance she
fell?
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(b) What was her velocity just before she was caught?

Answer 1

1 feet = 0.3048m (我不知道英制国家落体公式是不是也转换成m,中国是不使用英制的)
还是利用S=gt²/2这个公式
t² = 2*S/g = 2*12 * 0.3048/9.8 = 0.7464
t = 0.86(s)
(b)v = gt = 9.8 * 0.86 = 8.47(m/s)