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3 years ago

15

A rock falls from a tower that is 320 feet high. As it is falling, its height is given by the formula h equals 320 minus 16 t s

quared . How many seconds (in tenths) will it take for the rock to hit the ground (hequals0)?

1 answer:

RSB [31]3 years ago

4 0

Answer:

a. 4.5secs

Explanation:

From the question, the equation describing the height is given by

$h(t)=320-16t^{2}\\$

at the point when the rock hit the ground, the height,h will be zero.

Hence we can have

$h(t)=320-16t^{2}\\\\at h(t)=0\\0=320-16t^{2}\\hence \\320=16t^{2}\\t^{2}=\frac{320}{16}\\ t^{2}=20\\t=\sqrt{20}\\ t=4.47secs\\t=4.5sec\\$

hence the rock will hit the ground in 4.5secs

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