ShmoopTube

00:00

Yeah Whoa Okay Mass Shmoop er's Another question for you

00:05

here Wego Ana is playing with a tennis ball and

00:07

after five seconds she tosses it up in the air

00:10

The ball returns to her hand three seconds after she

00:13

tosses it assuming the height of the ball is zero

00:15

when it is in and his hand which of the

00:17

following equations models the height of the ball at time

00:20

and he is of age of he is greater than

00:23

our legal to zero Okay this kind of ugly isn't

00:28

it Alright grab your tennis racket and get ready to

00:30

deal with what this problem's serving the problem Asked about

00:34

modeling the height of the ball and it can be

00:36

assumed that the height is zero when the ball is

00:39

in Anna's And yeah we'll just assume that zero It's

00:42

in her hand at five seconds and then at three

00:45

seconds later I eat eight seconds later So the height

00:47

H of tea is zero when t equals five and

00:52

T equals eight and we need to make a quadratic

00:54

equation in which the following are true That is T

00:57

equals five or T minus five zero in T minus

01:00

eight zero rights That's quadratic and there's a little parable

01:03

a thing in the shape of the ball If you

01:05

want to think about it like that well this is

01:06

just like finding the X values I either roots of

01:09

the zeroes of a quadratic equation but will be working

01:13

backwards So H of tea is zero which is ah

01:17

quantity T minus five times quantity T minus eight Then

01:20

we just multiply everything through So you get T squared

01:22

minus thirteen T plus forty That's it So the answer

01:25

is a all the wrong answer Choices come from some

01:27

weird combination of wrong and attribution sze of eight and

01:31

five and negative positive numbers and all that stuff So

01:34

that's it It's a in uh say a Fran a 00:01:37.16 --> [endTime] have a ball

Full Transcript