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3 years ago

After heating up in a teapot, a cup of hot water is poured at a temperature of 204°F.

Mathematics

1 answer:

laila [671]3 years ago

4 0

Answer:

Question 1: 0.081 min⁻¹

Question 2: 168ºF

Explanation:

The missing equation is:

$T=T_a+(T_0-T_a)e^{-kt}$

You are given:

Ta = the temperature surrounding the object = 73ºF
T₀ = the initial temperature of the object = 204ºF
t = 2.5 min
T after 2.5 min = 180ºF

Question 1: Find the the value of k.

Substitute the data into the equation and solve for k:

$180\º=73\º+(204\º-73\º)e^{-k\cdot 2.5min}\\ \\ 107\º=131\ºe^{-k\cdot 2.5min}\\\\-k\cdot 2.5min=\ln (107/131)\\\\k=0.081min^{-1}$

Question 2: Find the Fahrenheit temperature of the cup of water, to the nearest degree, after 4 minutes.

Subsititute into the formula and compute:

$T=73\ºF+(204\ºF-73\ºF)e^{-0.081min^{-1}\times 4min}\\ \\ T=73\ºF+(131\ºF)(0.72325024)\\\\T=168\ºF$

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According to these three facts, which statements are true?

sveticcg [70]

We have that

1)Circle W has center (−3, 0) and radius 8
the equation of a circle W is
(x+3)²+(y)²=8²

2)Circle V is a translation of circle W, 2 units down.
the center of circle V--------> (-3,0-2)---------> (-3,-2)

3)Circle V is a dilation of circle W with a scale factor of 2.
then the radius circle V is 8*2------> 16 units
the equation of a circle V is
(x+3)²+(y+2)²=16²

therefore

case A. Circle V and circle W are similar.---------> is correct
because I can transform circle V to circle W using only translations, rotations and scaling (In the case of circles, no rotations are necessary).

case B. Circle V and circle W have the same center.-------> is not correct

case C. The radius of circle V is 16.-----------> is correct

case D. The center of circle V is (−5, 0).----------> is not correct

the answer is
 case A. Circle V and circle W are similar.---------> is correct
case C. The radius of circle V is 16.-----------> is correct

3 0

3 years ago

12.6% of RI 149 390bn

galina1969 [7]

Answer: RI 18,823.14

Step-by-step explanation:

I guess that we want to find the 12.6% of Rl 149,390

First, we assume that Rl 149,390 is the 100%

Then we can write an equation like:

Rl 149,390 = 100%

Then if the amount X is the 12.6%, we also have the equation:

X = 12.6%

Then we have the two equations:

X = 12.6%

Rl 149,390 = 100%

If we take the quotient between these two equations we get:

(X/Rl 149,390) = (12.6%/100%)

Solving this for X we get:

X = (12.6%/100%)*(Rl 149,390) = RI 18,823.14

7 0

3 years ago

What equals negative 4

galina1969 [7]

Your question is very vague, there is no multiple choice answers, your question lacks basically everything.

-2+(-2=4?

3 0

3 years ago

A distance AB is observed repeatedly using the same equipment and procedures, and the results, in meters, are listed below: 67.4

skad [1K]

Answer:

a) $\bar X =\frac{67.401+67.400+67.402+67.396+67.406+67.401+67.396+67.401+67.405+67.404}{10}=67.401$

b) The sample deviation is calculated from the following formula:

$s=\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

And for this case after replace the values and with the sample mean already calculated we got:

$s=0.0036$

If we assume that the data represent a population then the standard deviation would be given by:

$\sigma=\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n}}$

And then the deviation would be:

$\sigma =0.00319$

Step-by-step explanation:

For this case we have the following dataset:

67.401, 67.400, 67.402, 67.396, 67.406, 67.401, 67.396, 67.401, 67.405, and 67.404

Part a: Determine the most probable value.

For this case the most probably value would be the sample mean given by this formula:

$\bar X =\frac{\sum_{i=1}^n X_i}{n}$

And if we replace we got:

$\bar X =\frac{67.401+67.400+67.402+67.396+67.406+67.401+67.396+67.401+67.405+67.404}{10}=67.401$

Part b: Determine the standard deviation

The sample deviation is calculated from the following formula:

$s=\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

And for this case after replace the values and with the sample mean already calculated we got:

$s=0.0036$

If we assume that the data represent a population then the standard deviation would be given by:

$\sigma=\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n}}$

And then the deviation would be:

$\sigma =0.00319$

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3 years ago

The perimeter of the scalene triangle is 54.6 cm.

valina [46]

Are you sure it’s a scalene triangle because if you only know one side and all the other sides are different lengths then it’s impossible to computer unless we know angle measures. It would have to be isoceles or we would need angle measures

5 0

3 years ago