All categories

3 years ago

The initial temperature of a cup of tea is 200ºF. The surrounding temperature is 70ºF, and the value of the constant k is 0.6.

1 answer:

6 0

Newton's Law of Cooling states that the change of the temperature of an object is proportional to the difference between its own temperature and the ambient temperature over time.

Therefore when expressed mathematically, this is equivalent to:

dT = - k (T – Ts) dt

dT / (T – Ts) = - k dt

Integrating:

ln [(T2– Ts) / (T1– Ts)] = - k (t2 – t1)

Before we plug in the values, let us first convert the temperatures into absolute values R (rankine) by adding 460.

R = ˚F + 460

T1 = 200 + 460 = 660 R

Ts = 70 + 460 = 530 R

ln [(T2– 530) / (660 – 530)] = - 0.6 (2 - 0)

T2 = 569.16 R

T2 = 109 ºF

Answer: After 2 hours, it will be 109 ºF

You might be interested in

In the equation y = kx, what does the variable k represent?

anyanavicka [17]

Answer:

I think it B but I really don't know cause need like an example

8 0

3 years ago

The Mariners buy jerseys wholesale for $48 and sells for $468. What’s the markup rate?

AlekseyPX

Answer:

975%

Step-by-step explanation:

468/48 - 9.75

9.75 in percent form is 9.75*100=975%

Too much for a Mariners jersey if you ask me :D

8 0

3 years ago

(x-2y=-5) (2x + 4y =14) what is the value of y

dusya [7]

Sub x=-5+2y
2(-5+2y)+4y=14
y=3

6 0

3 years ago

Suppose the average price of gasoline for a city in the United States follows a continuous uniform distribution with a lower bou

Novay_Z [31]

Answer:

$P(X$

And we can use the cumulative distribution function given by:

$F(x) = \frac{x-a}{b-a} , a \leq X \leq b$

And for this case we can write the probability like this:

$P(X$

And then the final answer for this case would be $\frac{2}{3}=0.667$

Step-by-step explanation:

For this case we define our random variable X "price of gasoline for a city in the USA" and we know the distribution is given by:

$X \sim Unif (a=3.5, b=3.8)$

And for this case the density function is given by:

$f(x) = \frac{x}{b-a}= \frac{x}{3.8-3.5}=, 3.5 \leq X \leq 3.8$

And we want to calculate the following probability:

$P(X$

And we can use the cumulative distribution function given by:

$F(x) = \frac{x-a}{b-a} , a \leq X \leq b$

And for this case we can write the probability like this:

$P(X$

And then the final answer for this case would be $\frac{2}{3}=0.667$

5 0

3 years ago

brazil exports the most coffee in the world it cost approximately $2.55 to produce a pound of coffee.Also the us charges 20% tar

exis [7]

Answer:

I believe it is 3.1875.

Step-by-step explanation:

25% of 2.55 is 0.6375.

2.55 + 0.6375 = 3.1875.

3 0

3 years ago