Question

Please help

Answer 1

Answer:

Hence, option: B is correct (11.02 seconds)

Step-by-step explanation:

Spencer hits a tennis ball past his opponent. The height of the tennis ball, in feet, is modeled by the equation h(t) = –0.075t2 + 0.6t + 2.5, where t is the time since the tennis ball was hit, measured in seconds.

Now we are asked:

How long does it take for the ball to reach the ground?

i.e. we have to find the value of t such that height is zero i.e. h(t)=0.

$-0.075t2+0.6t+2.5=0$

or $0.075t^2-0.6t-2.5=0$

i.e. we need to find the roots of the above quadratic equation.

on solving the equation we get two roots as:

t≈ -3.02377 and t≈11.0238

As time can't be negative; hence we will consider the value of t as t≈11.0238.

Hence it takes 11.02 seconds for the ball to reach the ground.

Hence option B is correct (11.02 seconds).

Answer 2

Answer:

11.02 seconds

Step-by-step explanation:

Given : The height of the tennis ball, in feet, is modeled by the equation $h(t) = -0.075t^2 + 0.6t + 2.5$ where t is the time since the tennis ball was hit, measured in seconds.

To Find: How long does it take for the ball to reach the ground?  

Solution:

$h(t) = -0.075t^2 + 0.6t + 2.5$

Now we are supposed to find How long does it take for the ball to reach the ground , i.e. h = 0

$0 = -0.075t^2 + 0.6t + 2.5$

$-0.075t^2 + 0.6t + 2.5=0$

$t=11.02,-3.02$

So, time cannot be negative

So, it take 11.02 seconds for the ball to reach the ground