Question

Will award medal, i made this situation up for my study guide. please help

A building is 40ft. tall.
h(t)=-16t + 250t
a firework is launched from the top of that building at 150ft/sec
a.what is the equation for this situation
b.when will the firework land if it doesn't explode

Answer 1

C. make a table so it shows the hight from the time t=0 untill it hits the ground.

Answer 2

my mom made the situation. i don't know how to solve it.

Answer 3

ok, so do you know what t stands for?

Answer 4

argh, can't respond

Answer 5

sometimes it won't let me click post

Answer 6

so time it t, as in t=1 is time=1 second

Answer 7

crap gotta go

Answer 8

ask one of the helpers online

Answer 9

and np

Answer 10

It should be -16t^2, not -16t

Answer 11

This problem overall doesn't make sense; is velocity 150 ft/sec or 250 ft/sec?

Answer 12

my mom told me she wrote this and sent it to me to compleat it.

Answer 13

Those are two different problems.

Answer 14

for number 2 under task two, find whether the parabola opens upwards or downwards

Answer 15

i know it opens down.

Answer 16

For number three, it seems you need a height of a building to base the problem off of

Answer 17

Look at task one for context on task two, number three

Answer 18

and i picked the hight of a store here. which is roughly 40 ft.

Answer 19

Ok, forty feet.

Answer 20

k. nothing so far has helped me..?

Answer 21

Your equation for trajectory objects in this context will be h(t)=-16t^2 + your initial velocity, 150 times x + your starting height

Answer 22

task 2. number 1. how do i know how long it will take to hit the ground?

Answer 23

things have to be done in order otherwise it confuses me.

Answer 24

@Oops

Answer 25

Ok. use the h(t)=blah on your sheet to help you solve task 2, number 1

Answer 26

Hint= what is your initial forward velocity?

Answer 27

i don't know.

Answer 28

i don't even know what initial forward velocity means.?

Answer 29

@Oops ???

Answer 30

Your initial velocity is how fast the object is moving forward

Answer 31

In this instance, the object isn't moving forward at all, so your initial velocity=0

Answer 32

well it doesn't tell me that. i drop the thing straight down not forward.

Answer 33

you are making it more confusing. i am not even using that so it doesn't matter.

Answer 34

Ok, so your equation then would be \[h(t)=-16t^2 +40\] 40 is your starting height

Answer 35

ok. what does the h(t) mean.? i am compleatly clueless.

Answer 36

h(t) is just a fancy way of saying y; when t is your input, what you put in, h(t) will be your output, what you get out

Answer 37

ok

Answer 38

so how can it be solved?

Answer 39

When the tool hits the ground, your height will be equal to 0. So you don't know your input, t, but you know your intended output (h(t)), 0. Switch h(t) with 0 and solve the quadratic equation.

Answer 40

that made no sence.. what is quadratic equation? i really hate math it never makes sence.

Answer 41

@Oops ???

Answer 42

Are you homeschooled? Or is this a school assignment

Answer 43

homeschooled.

Answer 44

i actually find text books and teach my self. my mom is smart with math so she helps me with that one. she made me this. but i don't understand it.

Answer 45

if you solve it for me i can remember it. like show me the steps of how to solve it. i don't know the steps on how to solve it.

Answer 46

You're jumping ahead of yourself then. Learn about what polynomials are and how to factor them, and then learn about the basics of a quadratic equation. THEN start doing problems like this. (Absolute value equations and inequalities as well as systems of inequalities don't hurt either!)

Answer 47

well that will take to long. my mom wanted me to solve this by the end of today.

Answer 48

i have heard of these things. but i can't remember how to work them out. like i said. if you show me how to solve one i may be able to work out the rest.

Answer 49

Tell your mom that the spooky internet goblins are telling her to tell you to build up a foundation before moving onto quadratic equations!!!

Answer 50

i am on algebra 2. i have studied all the other math. i JUST CAN"T REMEMBER HOW TO SOLVE IT!

Answer 51

i am not a child and that spooky internet gobiln statement was extramly offensive.
i am almost 18 tf. please just remind me how to solve it that is litterally all i am asking for.

Answer 52

Oh, if you're on algebra 2 then quadratics should just be a review for you

Answer 53

quadratic equations are basically equations with the standard form\[y= ax^2 + bx + c\]

Answer 54

exactly. like i said I just can't remember these things.

Answer 55

Ok, that's fair

Answer 56

i don't remember how to solve the equation.

Answer 57

giving me the equation does not tell me how to solve it. thats what i need help with.

Answer 58

There are a few good ways to solve quadratics; the easiest way to solve an equation like \[ax^2 + c\] is to move c to the other side, divide by a, and take the square roots of both sides

Answer 59

that is not the equation for the problem i have to solve?

Answer 60

how do i solve this h(t)=−16t2+40

Answer 61

in your situation, \[16t^2=40\]\[t^2=2.5\]\[t = \sqrt{2.5}\]

Answer 62

huh? that is still not the full equation i am working with...?

Answer 63

how did you get thoes numbers..?

Answer 64

Change h(t) to 0, like I stated above

Answer 65

that doesn't make sence. can you use the whole equation. and go step by step.?

Answer 66

\[0=-16t^2 + 40\]\[16t^2= 40\]\[t^2=2.5\]\[t=\sqrt{2.5}\]

Answer 67

okay.. so then how long does it take for the tool to reach the ground?

Answer 68

\[\sqrt{2.5}\] seconds

Answer 69

so less than a second?

Answer 70

about 1.6 seconds

Answer 71

ok

Answer 72

so now task 2 3.a/ what would the equation be?

Answer 73

would it be 150 instead of 40 or what?

Answer 74

It would be y=-16t^2 + initial velocity times t + starting height

Answer 75

so in this case, \[y=-16t^2 + 150t + 40\]

Answer 76

huh. okay. would i solve it the same way for part B. to get how long it would take before it hits the ground?

Answer 77

No, you can't take the square root like what we did earlier.

Answer 78

There's either the quadratic equation, completing the square, or factoring

Answer 79

then how would i know how long it takes untill it hits the ground?

Answer 80

You use those three to find the zeroes of the quadratic equation (when x=0)

Answer 81

there is no x in the equation though.

Answer 82

I highly encourage you to look at some tutorials online to refresh yourself on what factoring, completing the square, and the quadratic equation are (too much for me to explain through a chatbox!)

Answer 83

t and x are synonymous

Answer 84

well if i have to solve it differently. just show me how to solve it. and i can usually remember it after doing it a few times.

Answer 85

You can change t for x, if it makes you more comfortable

Answer 86

All three of those aren't something you can learn to do in a day; if you've completely forgotten all of that, I would take one or two days to refresh on what completing the square, factoring, and the quadratic equation are

Answer 87

To help you out right now, I'll just show you step-by-step the quadratic formula

Answer 88

i know what they are. just i don't know how to apply them to this certain equation. to solve for how long untill the firework hits the ground.

Answer 89

The quadratic formula is \[y=\frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }\]

Answer 90

Your equation is\[y=-16t^2 + 150t + 40\]where a=-16, b=150, and c=40

Answer 91

Plugging in a, b, and c into the quadratic formula:
\[y=\frac{ -(150)\pm \sqrt{(150)^2-4(-16)(40)}}{ 2(-16) }\]

Answer 92

\[y=\frac{ -150\pm \sqrt{22500 + 2560} }{ -32 }\]

Answer 93

okay.? then what.

Answer 94

\[y=\frac{-150\pm \sqrt{25060}}{-32}\]

Answer 95

\[y=\frac{-150\pm158.3}{-32}\](158.3 is rounded)