Question

A ball is thrown into the air from a height of 4 feet at time t = 0. The function that models this situation is
h(t)= -16t2 + 64t + 4, where t is measured in seconds and h is the height in feet. Use this information to answer the following questions.
After how many seconds will the ball hit the ground?

Answer 1

Answer: So the ball hits the ground 4.06 secs after it's kicked.

Step-by-step explanation:h(t)= -16t^2 +64t +4

              h(t)= -4( 4t^2 -16t -1)  so a=4 b=-16 c=-1

Use Quadratic Formula: x=( -b+/- (b^2-4ac)^1/2)/ 2a

 (16+/- ( 256-(4)(4)(-1))^1/2)/8= (16 +/- (272)^1/2)/8

x= (16+/-16.49)/8  ---->x=32.49/4= 4.062 sec

x=(16-16.49)/8  -----> x= -0.49/8= -0.06

So the ball hits the ground 4.06 secs after it's kicked.