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2 years ago

13

Which statements about squares and equilateral triangles are true?

1 answer:

12345 [234]2 years ago

5 0

Answer,a and b, sorry if they are wrong

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Newton's law of cooling states that the temperature of an object changes at a rate proportional to the difference between its te

Aleonysh [2.5K]

Answer:

t=5.18 minute

Step-by-step explanation:

Using Newton's law of cooling

$\frac{dT}{dt}=-k(T-T_{s})$

T is temperature of a cup of coffee at any time t $T_{s}$ , is the temperature of the surrounding and k is a constant of proportionality in this negative because temperature is decreasing.

$T(0)=190\\T(1)=170\\T_{s}=66$

$\frac{dT}{dt}=-k(T-T_{s})\\\frac{dT}{(T-T_{s})}=-k*dt\\\int\limits {\frac{1}{T-T_{s} } } \, dT=-\int\limits {k} \, dt\\ln(T-T_{s})=k*t+C\\e*ln(T-T_{s})=e^{k*t+C} \\T-T_{s}=e^{k*t}*e^{C}\\e^{C}=C\\T-T_{s}=e^{k*t}*C\\T=T_{s}+e^{k*t}*C$

To find constant knowing the time and the temperature the first step of the change of energy in cup of coffee

$T=T_{s} +e^{-k*t}*C\\ C=190-66=124\\170=66+124*e^{-k*2}\\ 170-66=124*e^{-k*2}\\ln(\frac{104}{124})=ln*e^{-k*2}\\-0.175=-k*2\\k=0.08794$

Now using the constant of decreasing can find the time to be a 145 temperature the cup of coffee

$145=66+124*e^{-k*t} \\145-66=124*^{-0.087*t}$

$ln(0.637)=ln*e(-0.087*t)\\-0.45=-0.087*t\\t=5.18minutes$

4 0

3 years ago

Can someone answer it

Troyanec [42]

Answer what? This question? Oh, I'm answering it right now. Did you have another question out? Well, I can't see it.

3 0

3 years ago

Find the ratio of:<br> (a) 5 km to 400 m<br> (b) 2 hours to 160 minutes

aleksandr82 [10.1K]

Answer:

Answer - a) 1:80

b) 1:80

Step-by-step explanation:

All the ratio should be written in lowest form. these are the answers for both the questions.

Pls Mark Brainliest !!!!!!!!!!!!!!

6 0

1 year ago

Read 2 more answers

Whoever gives me the correct answer to this will get a brainlest <br> I need the answer ASAP!

Amiraneli [1.4K]

Volume of cone= 1/3πr^2h

8842.24 m^3= 1/3πr^2h

1/3*3.14*33*r^2= 8842.24m^3

r^2 = 8842.24*3/3.14*33

r^2= 26526.72/103.62

r^2 = 256

r= √256

r= 16m

Hope it helps. Please mark brainliest.

8 0

2 years ago

PLEASE HELP. i need to show my work for<br> the correct answer. please help

e-lub [12.9K]

Answer:

I THINK IM WRONG BUT

Step-by-step explanation:

X3 NUZZELS POINCES ON U

7 0

2 years ago