ThatCooGuy101
contestada

Arianna kicks a soccer ball off the ground and into the air with an initial velocity of 42 feet per second. Assume the starting height of the ball is 0 feet. Approximately how long does it take until the soccer ball hits the ground again?
1.3 secs
2.6 secs
16.0 secs
27.6 secs

Respuesta :

irspow
a=g

v=⌠g dt

v=gt+C, where C=v initial

v=gt+vi

h=⌠v dt

h=gt^2/2+vit+C, where C=h initial

h=gt^2/2+vit+hi

We are told that vi=42 ft/s, hi=0, and we know g≈-32 ft/s^2 so

h(t)=-16t^2+42t

The ball will hit the ground when h=0 so

-16t^2+42t=0

-2t(8t-21)=0, since t>0

8t-21=0

8t=21

t=21/8

t=2.625 sec

t≈2.6 sec (to nearest tenth of a second)

The time taken by the ball to hit the ground again will be 2.6 seconds. Then the correct option is B.

What is kinematics?

It is the study of the motion of a body without considering mass. And the reason behind them is neglected.

Arianna kicks a soccer ball off the ground and into the air with an initial velocity of 42 feet per second.

Assume the starting height of the ball is 0 feet.

Then the time taken by the ball to hit the ground again will be

[tex]\rm T = \dfrac{2v_o}{g}\\[/tex]

We know that the acceleration due to gravity is 32.174 ft per second square.

Then we have

[tex]\rm T = \dfrac{2 \times 42}{32.174}\\\\T = 2.6 \ sec[/tex]

More about the kinematics link is given below.

https://brainly.com/question/25638908

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