Question

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 squared . How many seconds​ (in tenths) will it take for the rock to hit the ground ​(hequals​0)?

Answer 1

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