Question

The height of an overhand volleyball serve can be modeled as h=-16t^2+20t+6. After how many seconds is the ball 11 feet.

Answer 1

Answer:

0.9043secs and 0.3456secs

Step-by-step explanation:

Given the height of an overhand volleyball modeled as h=-16t^2+20t+6.

If the height is 11feet, then;

11 = -16t^2+20t+6.

-16t^2+20t+6 - 11 = 0

-16t^2+20t-5 = 0

Multiply thriugh by -1

16t^2-20t+5 = 0

Factorize

t = 20±√20²-4(16)(5)/2(16)

t = 20 ±√400-320/32

t = 20 ±√80/32

t = 20 ±4√5/32

t = 20±8.94/32

t = 28.94/32 and 11.06/32

t = 0.9043 and 0.3456

Hence the required time are 0.9043secs and 0.3456secs