Question

The height of an object after it is released can be modeled by the function f(t)=-16t^2+vt+s, where t is the number of seconds after the object is released, v is the upward speed at release, and s is the starting height. If a quarterback throws a ball from his hand 6 feet in the air at a speed of 25 feet per second, how much time does his teammate have to catch the ball?

about 1.45 seconds
about 1.77 seconds
about 6 seconds
about 25 seconds

Answer 1

B.) about 1.77 seconds

Answer 2

Answer about 1.77 seconds.

f(t) = -16 t^2 + 25t + 6

f(t) = height.

hieght = 0 = -16t^2 + 25t + 6

Find t using the quadratic formula,

t = ( - 25 +/- √[25^2 - 4 (-16)(6)] ) / [2*(-16)]

t = [-25 +/- √ (625 + 384) ] / -32

t = [-25 +/- 31.76] / -32.

You will obtain two results one positive and one negative. Take the positive only as the other one has no physical meaning. t = 1.77 s.