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katrin [286]
3 years ago
14

A sandbag is released from a hot air balloon that is 400 ft above the ground. Using the falling object model, h = −16t^2 + s, wh

ere h = height in feet, t = time in seconds, and s = initial height in feet, how long will it take for the sandbag to hit the ground? A. 4 seconds B. 5 seconds C. 20 seconds D. 25 seconds

Mathematics
1 answer:
Bogdan [553]3 years ago
7 0

Answer:

  B. 5 seconds

Step-by-step explanation:

A graphing calculator shows the answer easily.

__

h(t) = 0 = -16t^2 +400

t = √(400/16) = 5

It will take 5 seconds for the sandbag to hit the ground.

You might be interested in
The length of a rectangle is four times its width. If the area of the rectangle is 324m^2, find its perimeter.
Anuta_ua [19.1K]

Answer:

perimeter=90

Step-by-step explanation:

We know that the length is four times the width, so:

l=4w

We also know the area, which is 324 m². The formula for area:

A=l*w

Insert the known values:

324=(4w)*w

Solve for w. Simplify by removing parentheses:

324=4w*w\\324=4w^2

Divide 4 from both sides to isolate the variable:

\frac{324}{4}=\frac{4w^2}{4}  \\\\81=w^2

Find the square root of both sides:

\sqrt{81} =\sqrt{w^2} \\\\w=9

The width is 9 m.

We know the width. Now find the length by using the area formula and inserting known values:

324=l*9

Solve for l. Divide both sides by 9:

\frac{324}{9}=\frac{l*9}{9}\\\\  l=36

The length of the rectangle is 36. (You can check: 4 times 9 is 36)

Now find the perimeter:

P=2l+2w

Insert values:

P=2(36)+2(9)\\\\P=72+18\\\\P=90

The perimeter is 90 m.

5 0
3 years ago
Consider a sequence defined by the recursive rule f(1) = 15; f(n)=f(n - 1) - 6 for n 2. Choose True or
Shkiper50 [21]

Answer:

The second term of the sequence is 8  False ⇒ B

The third term of the sequence is 3  True ⇒ A

The fourth term of the sequence is -3  True ⇒ A

Step-by-step explanation:

The form of the recursive rule is:

f(1) = first term; f(n) = f(n - 1) + d, where

  • f(1) is the first term
  • f(n) is the nth term
  • f(n - 1) is the term before the nth term
  • d is the common difference

∵ f(1) = 15, f(n) = f(n - 1) - 6 for n ≥ 2

∴ The first term = 15

∴ d = -6

let us find the 2nd, 3rd, and 4th terms

∵ n = 2

∴ f(2) = f(1) - 6

∵ f(1) = 15

∴ f(2) = 15 - 6 = 9

∴ The second term is 9

∴ The second term of the sequence is 8  False

∵ n = 3

∴ f(3) = f(2) - 6

∵ f(2) = 9

∴ f(3) = 9 - 6 = 3

∴ The third term is 3

∴ The third term of the sequence is 3 True

∵ n = 4

∴ f(4) = f(3) - 6

∵ f(3) = 3

∴ f(4) = 3 - 6 = -3

∴ The fourth term is -3

∴ The fourth term of the sequence is -3 True

5 0
3 years ago
Why is the answer A? Plzzz explain.
Contact [7]

Answer:


Step-by-step explanation:

f(x) = x^2 + 4x + 4

f(x + a) = (x + a)^2 + 4(x + a) + 4

f(x + a) = x^2 + 2ax + a^2 + 4x + 4a + 4   Now combine like terms and use the distributive property.

f(x + a) = x^2 + (2a + 4)x + a^2 + 4a + 4

We are told that f(x + a) = x^2 - 6x + 9

So that means that

2a + 4 = - 6      Subtract 4 from both sides.

2a = - 6 - 4

2a = - 10          Divide by 2

a = - 10/2

a = - 5.            

But you are not finished. You have to check the last part.

a^2 + 4x + 4 = 9

(a + 2)^2 = 9

Take the square root of both sides

sqrt(a+ 2)^2 = +/- 3

a+2 = 3

a = 1.

Does this work or is it extraneous? It is extraneous because it will not work for  2(a) + 4 = - 6  

You get 6 = - 6 which is not correct. But you did give the second best answer.

a + 2 = - 3

a = - 3 - 2

a = - 5 which agrees with your previous answer.

===========

This is an extremely hard or tricky or sneaky problem. It takes a lot of conniving to get the right answer and 1 is not a left field answer. It just does not happen to be correct.

8 0
3 years ago
Need help plz i show me how to do it plz :)
DaniilM [7]
I’m pretty sure you multiply the sides your you find the formulas for the hight and width
8 0
3 years ago
Read 2 more answers
 Jamal works at a sporting goods store on the weekends. Suppose last weekend he worked
rusak2 [61]

Answer:

$8.8 per hour

Step-by-step explanation:

Well, the equation is simple.

Time (hours) * Money (per hour) = Total

We know the time he worked for and the total amount he earned, so just replace in this equation and find the unknown number

12.5 * money = 110

To find the money he earns per hour we should just simply divide the total amount he earned by the hours he spent working

money = 110/12.5

money = 8.8$

You can also check it out to make sure it's correct.

If he earns 8.8$ per hour and worked for 12.5 hours how much he'll earn? Let's find out

8.8 * 12.5 =?

8.8 * 12.5 = 110, the same total amount so our solution must be correct.

3 0
2 years ago
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