The function sr 16r2 models the distance sr in feet that an

The function s(r) = 16r^2 models the distance, s(r), in feet, that an object falls in r seconds. Use this function and the square root property to solve Exercise 81-82. Express answers in simplified radical form. Then use your calculator to find a decimal approximation to the nearest tenth of a second. A sky diver jumps from an airplane and falls for 4800 feet before opening a purchase. For how many seconds was the diver in a free fall?

Solution

s(t) = 16t^2

So, s(t) = 4800 feet

4800 = 16t^2

t^2 = 4800/16 = 1200/4 =300

Take square root on both sides:

t = sqrt300

t = 10sqrt(3) = 17.32 = 17.3 sec