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2 years ago

If y varies inversely as the square of x and y= 7/48 when x=4 find y when x=3

Mathematics

1 answer:

kolezko [41]2 years ago

7 0

the answer is 7/27 if x= 3

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I did 4 more problems than Manuel how many problems did I do

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4 more than Manuel did

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3 years ago

Use Hooke's Law to determine the work done by the variable force in the spring problem. A force of 450 newtons stretches a sprin

vlada-n [284]

Answer:

The work done is 202.50Nm

Step-by-step explanation:

Given

$F =450N$

$x_1 = 30cm$

$x_2 = 60cm$

Required

The work done

First, we calculate the spring constant (k)

$F = kx_1$

$450N = k *30cm$

$k = \frac{450N}{30cm}$

$k =15N/cm$

So:

$F = kx_1$

$F(x) = 15x$

The work done using Hooke's law is:

$W =\int\limits^a_b {F(x)} \, dx$

This gives:

$W =\int\limits^{60}_{30} {15x} \, dx$

Rewrite as:

$W =15\int\limits^{60}_{30} {x} \, dx$

Integrate

$W =15 \frac{x^2}{2}|\limits^{60}_{30}$

This gives:

$W =15 *\frac{60^2 - 30^2}{2}$

$W =15 *\frac{2700}{2}$

$W =15 *1350$

$W =20250N-cm$

Convert to Nm

$W =\frac{20250Nm}{100}$

$W =202.50Nm$

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3 years ago

How did you figure out the answers ? how did you work it out ?

Maksim231197 [3]

How did who figure out what answer?

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3 years ago

Sample size: A researcher is trying to decide how many people to survey. Which of the following sample sizes will result in a co

oksian1 [2.3K]

Answer:

Step-by-step explanation:

Given that a researcher is trying to decide how many people to survey.

We have confidence intervals are intervals with middle value as the mean and on either side margin of error.

Confidence interval = Mean ± Margin of error

Thus confidence interval width depends on margin of error.

Margin of error = $Critical value *\frac{\sigma}{\sqrt{n} }$

Thus for the same confidence level and std deviation we find margin of error is inversely proportional to square root of sample size.

Hence for small n we get wide intervals.

So if sample size = 300, the researcher will get wider confidence interval

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4 years ago

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koban [17]

The total cost for a $1,200 washing machine is $1,200. In the real world it would be 1,200 + tax.

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3 years ago

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