Hhhhhheeeeeeeeeeelllllllppppppp

A rocket is fired with an initial vertical velocity of 40 m/s from a launch pad 45 m high, and its height is given by the formul

N76 [4]

Answer:

1) 125 meters

2) For 9 seconds.

Step-by-step explanation:

The rocket's height is given by the formula $-5t^2+40t+45$ .

Notice that this is a quadratic.

Part 1)

Since this is a quadratic, the highest height the rocket goes will be the vertex of our quadratic. Remember that the vertex of a quadratic in standard form is:

$(-\frac{b}{2a}, f(-\frac{b}{2a}))$

So, let's identify our coefficients. The standard quadratic form is:

$ax^2+bx+c$

Therefore, in this case, our a is -5, b is 40, and c is 45.

So, let's find the x-coordinate of our vertex. Substitute 40 for b and -5 for a. This yields:

$x=\frac{-(40)}{2(-5)}$

Multiply and reduce. So:

$x=-40/-10=4$

Now, substitute 4 for t to find the height. So:

$-5(4)^2+40(4)+45$

Evaluate:

$=-5(16)+40(4)+45$

Multiply and add:

$=-80+160+45=125\text{ meters}$

Therefore, the highest the rocket goes up is 125 meters.

Part 2)

To find out for how much time the rocket is in the air, we can think about after how many seconds after launch will the rocket land.

If the rocket lands, the height h will be 0. So, we can set our expression equal to 0 and solve for t:

$-5t^2+40t+45=0$

First, let's divide everything by -5. This yields:

$t^2-8t-9=0$

We can factor:

$(t+1)(t-9)=0$

Zero Product Property:

$t+1=0\text{ or } t-9=0$

Solve for t:

$t=-1\text{ or } t=9$

In this case, since t is our time in seconds, -1 seconds does not make sense. So, we can remove -1 from our solution set.

Therefore, 9 seconds after launch, the rocket will touch the ground.

Therefore, the rocket was in the air for 9 seconds.

And we're done!

6 0

3 years ago

What is the probability of not drawing a card 6 or greater from a regular deck of cards?

Mamont248 [21]

Ok so there are 52 cards in a deck if you take all the cards that have the number 6 which is only 4 cards so 52-4 = 48 cards without any 6 so the ratio is 48/52
chances.

If you're trying to take any card that is greater than 6 its a little more complex there is T,2,3,4,5,6,7,8,9,10,B,Q,K so you have to tack away 6,7,8,9,10,B,Q,K from 4 rows so 8 x 4 =32 cards 52-32= 20 so the probability of not having any cards greater than 6 is 20/52

3 0

3 years ago

J.k. Rowling and R.L. Stone are both ready hunger games . J.k. Reads 35 pages every 2 hours and R.L. Reads 45 pages every 3 hour

san4es73 [151]

Answer:

The rate of change for each reader is :

For J K Rowling : 17 and a half pages per hour

For R L Stone : 15 pages per hour

Step-by-step explanation:

Here the reading rate of each reader is given as:

J.K. Reads 35 pages every 2 hours.

So, the number of pages read by J K in 2 hours = 35 pages

⇒ The number of pages read per hour = 35 / 2 = 17 . 5 pages

So, the pages read by J K Rowling in 1 hour is 17 and a half pages.

R L Stone reads 45 pages every 3 hours.

So, the number of pages read by R L in 3 hours = 45 pages

⇒ The number of pages read per hour = 45 / 3 = 15 pages

So, the pages read by R L Stone in 1 hour is 15 pages.

Hence, the rate of change for each reader is :

For J K Rowling : 17 and a half pages per hour

For R L Stone : 15 pages per hour

5 0

3 years ago

5 screen shots plz help plz will choose brianyest and will give 19 pts

Taya2010 [7]

Tigers! Have a great day!

7 0

3 years ago

A second game uses spinner B. A player must spin a Wto win. Explain how to find the experimental probability of spinning a W.

Volgvan

Answer:

sorry foe being late

Step-by-step explanation:

8 0

3 years ago