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Reptile [31]
2 years ago
13

A model rocket is launched with an initial upward velocity of 138 ft/s. The rocket's height h (in feet) after 1 seconds is given

by the following.
h = 138t-16t^2
Find all values of 1 for which the rocket's height is 78 feet.
Round your answer(s) to the nearest hundredth.
(If there is more than one answer, use the "or" button.)
Mathematics
1 answer:
insens350 [35]2 years ago
8 0

Answer:

t = 8.017 or 0.608 (nearest hundredth)

Step-by-step explanation:

h = 138t-16t^2

when h = 78:

\implies 138t-16t^2=78

\implies 16t^2-138t+78=0

Using quadratic formula:

t=\dfrac{138 \pm\sqrt{(-138)^2-(4 \cdot 16 \cdot 78)} }{2 \cdot 16}

\implies t=\dfrac{138 \pm\sqrt{14052} }{32}

\implies t=8.017, t = 0.608

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Answer:

230

Step-by-step explanation:

30 times 90 equalls 230

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3 years ago
This helicopter has a rotor that moves at a rate of 600 spins per minute while flying. Which statement is supported by this info
jeka57 [31]

Answer: d. The helicopter rotor will spin 36,000 times in 1 hour

Step-by-step explanation:

Option A is wrong because in 40 minutes the rotor will spin:

= 40 * 600

= 24,000 times

Option B is wrong because we cannot know the number of times the rotor will spin before being lifted off of the ground with the details given.

Option C is wrong because in 3 hours the rotor will spin:

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5 0
3 years ago
Please don't leave half an answer for the points!
vovikov84 [41]

Answer:

  1. T . . . labeling shown below
  2. U
  3. R
  4. S

Step-by-step explanation:

Matrix multiplication of A(a rows, b columns) and B(b rows, c columns) will result in a product matrix of AB(a rows, c columns). This fact can be used to reduce the number of candidates for each product.

For the given factor tiles, the resulting product dimensions will be ...

  [2, 3]  [3, 2]  [2, 2]   ⇒  Q, R, S

  [2, 3]  [3, 3]  [3, 2]   ⇒   T, U, V

  [3, 3]   ⇒   W

1. For this 2×3 product, candidates are Q and T. The upper left term for the product in Q is (2)(3) +(1)(7) +(0)(8) = 13. The appropriate choice is T.

2. For this 3×3 product, candidates are U and W. The upper left term for the product in U is 9(2) +1(2) +9(5) +5(1) = 18 +2 +45 +5 = 70. The appropriate choice is U.

3. For this 3×2 product, candidates are R and V. The upper left term for the product in R is 1(4) +2(0) +4(1) = 4 +0 +4 = 8. The appropriate choice is R.

4. For this 2×2 product, there is only one candidate: S.

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2 years ago
Write the standard form of a line that passes through the given points (4,7) and (0,7)
VARVARA [1.3K]

The slope-intercept form:

y=mx+b

m - slope

b - y-intercept → (0, b).

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Calculate the slope:

m=\dfrac{7-7}{0-4}=\dfrac{0}{-4}=0

Therefore we have y=0x+7=7

The standard form: Ax+By=C

<h3>Answer: y = 7.</h3><h3><em>It's a horizontal line.</em></h3>
4 0
3 years ago
PLEASE HELP ME! IM ON A TIMED QUIZZZZ
viktelen [127]

Answer:


Step-by-step explanation:

Part A: 20 shows $20 which Cory earns by mowing one lawn. 9 shows $9 which he earns by trimming one hedge. x shows the number of lawns. y shows the number of hedges. Part B: There are two terms in this expression. 20x which shows the total earning of Cory by mowing lawns. 9y which shows his earning by trimming hedges. It can be judged by the description of rates explained in part A. Part C: From explanation given in Part C, we can easily see that the expression 9y is used for the total earned from trimming hedges.



4 0
3 years ago
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