Mary pitches a ball. the initial height is 4 ft and velocity 55 ft per second. when will the ball hit the ground?

t = 3.5 sec

Step-by-step explanation:

The equation that represents the position of the ball as a function of time is the following:

Where:

= Initial position of the ball (4 feet tall)

= Initial speed of the ball (55feet / s)

a = acceleration (9.8 , or in this case 32.16)

t = time in seconds

Then we want to know how long it takes to get to the ground, for this we equal h (t) = 0 and clear t.

So:

Solving the second degree equation we have:

t = -0.071 sec

t = 3.5 sec

We must take the positive solution.

So:

t = 3.5 sec

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!