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Morgarella [4.7K]

3 years ago

14

Pablo and max's follows a flight pattern approximatley modled by the equation h(t)=-8t^2+16t+2 where h(t)is their rocket's heigh

t in meters t seconds after launch. How many seconds was their rocket in the air

1 answer:

kodGreya [7K]3 years ago

7 0

Answer: 2.11 s

Step-by-step explanation:

Given

Equation of rockets height is given by

$\Rightarrow h(t)=-8t^2+16+2$

Height will be zero once the rocket lands on the ground

So, we can write

$\Rightarrow h(t)=0\ \text{or}\ -8t^2+16t+2=0\\\Rightarrow 8t^2-16t-2=0\\\\\Rightarrow t=\dfrac{16\pm \sqrt{(-16)^2-4(8)(-2)}}{2\times 8}\\\\\Rightarrow t=\dfrac{16\pm \sqrt{320}}{16}\\\\\text{Neglecting negative value of t}\\\\\Rightarrow t=\dfrac{16+17.888}{16}=2.11\ s$

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Austen needs to buy a bathroom mirror that is 2 feet wide and 3 feet long. If the mirror

PtichkaEL [24]

<h2><u>Question :-</u></h2>

Austen needs to buy a bathroom mirror that is 2 feet wide and 3 feet long. If the mirror sells for $5.00 per square foot, what will the total cost of the mirror be?

<h3>____________________</h3>

<h2><u>Solution :-</u></h2>

<h3><u>Given Information :-</u></h3>

<u>Length of the mirror Austen needs to buy ➢</u> 3 ft
<u>Width of the mirror Austen needs to buy ➢</u> 2 ft
<u>Cost of mirror per square foot ➢</u> $5.00

<h3><u>To Find :-</u></h3>

Total cost of the mirror Austen needs to buy.

<h3><u>Formula Used :-</u></h3>

Area of Mirror = Length × Width
Total cost of mirror = Area of mirror × Cost of mirror per square foot

<h3><u>Calculation :-</u></h3>

<u>Area of mirror :-</u>

<em><u>Substituting the values given in the 1st formula, We get, </u></em>

⇒ Area of mirror = ( 3 × 2 ) ft²

⇒ Area of mirror = 6 ft²

<u>Now finding the total cost of mirror,</u>

<em><u>Substituting the values calculated above in the 2nd formula, We get </u></em>

⇒ Total Cost of mirror = $ ( 6 × 5.00 )

⇒ Total Cost of mirror = $30

<h3>___________________</h3>

<h2><u>Final Answer :-</u></h2>

Total cost of the mirror Austen needs to buy will be $30

<h3>____________________</h3>

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3 years ago

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Answer: C (0,3) because the two lines meet at the point (0,3)

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3 years ago

An automobile manufacturer has given its van a 59.5 miles/gallon (MPG) rating. An independent testing firm has been contracted t

LekaFEV [45]

Answer:

The pvalue of the test is 0.0124 < 0.1, which means that there is sufficient evidence at the 0.1 level to support the testing firm's claim.

Step-by-step explanation:

An automobile manufacturer has given its van a 59.5 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the actual MPG for this van since it is believed that the van has an incorrect manufacturer's MPG rating:

At the null hypothesis, we test if the mean is the same, that is:

$H_0: \mu = 59.5$

At the alternate hypothesis, we test that it is different, that is:

$H_a: \mu \neq 59.5$

The test statistic is:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

In which X is the sample mean, $\mu$ is the value tested at the null hypothesis, $\sigma$ is the standard deviation and n is the size of the sample.

59.5 is tested at the null hypothesis:

This means that $\mu = 59.5$

After testing 250 vans, they found a mean MPG of 59.2. Assume the population standard deviation is known to be 1.9.

This means that $n = 250, X = 59.2, \sigma = 1.9$

Value of the test statistic:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

$z = \frac{59.2 - 59.5}{\frac{1.9}{\sqrt{250}}}$

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Pvalue of the test and decision:

The pvalue of the test is the probability of finding a mean that differs from 59.5 by at least 0.3, which is P(|Z|>-2.5), which is 2 multiplied by the pvalue of Z = -2.5.

Looking at the z-table, Z = -2.5 has a pvalue of 0.0062

2*0.0062 = 0.0124

The pvalue of the test is 0.0124 < 0.1, which means that there is sufficient evidence at the 0.1 level to support the testing firm's claim.

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3 years ago

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lara31 [8.8K]

Answer:

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3 years ago

Read 2 more answers

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guajiro [1.7K]

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$15=45e^{-0.05t}$

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$\frac{1}{3}=e^{-0.05t}$

Now we will switch sides:

$e^{-0.05t}=\frac{1}{3}$

Let us take natural log on both sides of equation.

$\text{ln}(e^{-0.05t})=\text{ln}(\frac{1}{3})$

Using natural log property $\text{ln}(a^b)=b\cdot \text{ln}(a)$ , we will get:

$-0.05t\cdot \text{ln}(e)=\text{ln}(\frac{1}{3})$

$-0.05t\cdot (1)=\text{ln}(\frac{1}{3})$

$-0.05t=\text{ln}(\frac{1}{3})$

$t=\frac{\text{ln}(\frac{1}{3})}{-0.05}$

$t=\frac{\text{ln}(\frac{1}{3})\cdot 100}{-0.05\cdot 100}$

$t=\frac{\text{ln}(\frac{1}{3})\cdot 100}{-5}$

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Therefore, it will take $20\text{ln}(3)$ years for area of the glacier to decrease to 15 square kilo-meters.

6 0

3 years ago