1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ExtremeBDS [4]
2 years ago
11

The temperature of a cup of coffee varies according to Newton's Law of Cooling: dT dt equals negative k times the quantity T min

us A, where T is the temperature of the coffee, A is the room temperature, and k is a positive constant. If the coffee cools from 100°C to 90°C in 1 minute at a room temperature of 25°C, find the temperature, to the nearest degree Celsius of the coffee after 4 minutes.
74
67
60
42
Mathematics
1 answer:
denis23 [38]2 years ago
4 0

Answer:

  (b)  67

Step-by-step explanation:

A solution to the differential equation describing the temperature according to Newton's Law of Cooling could be written as ...

  T = (final temp) + (initial difference)×(decay factor)^t

where the decay factor is the fraction of change during 1 unit of time period t.

__

Here, the initial difference of 100-25 = 75 degrees decays to 90-25 = 65 degrees in 1 minute. So, the units of t are minutes, the decay factor is 65/75, the initial difference is 75 degrees, and the final temperature is 25 degrees. That lets us write the equation as ...

  T = 25 +75(65/75)^t

Then for t=4, the temperature is ...

  T = 25 +75(13/15)^4 ≈ 67.3 . . . . degrees

After 4 minutes the temperature of the coffee is about 67 degrees.

You might be interested in
You spin the spinner and flip a coin. Find the probability of the compound event.
Nitella [24]

Answer:

1/10

Step-by-step explanation:

The probability of flipping heads is 1 out of 2 or 1/2

The probability of getting a 5 on the spinner is 1/5

The probability of getting both is 1/2  *  1/5 = 1/10

You should try this out by listing all the ways this can happen.

Spinner         Coin

1                     H

2                    H

3                    H

4                    H

<em><u>5                    H</u></em>

1                     T

2                    T

3                    T

4                    T

5                    T

There are 10 ways of this problem giving results. Only 1 of them is correct.

5 0
2 years ago
Which shows the correct substitution of the values a, b, and c from the equation –2 = –x + x² – 4 into the quadratic formula?
Romashka [77]
-2 = - x + x^2  -4 => x^2 - x - 4 + 2 = 0

x^2 - x - 2 = 0

a is the coefficient of x^2 => a = 1

b is the coefficient of x => b = - 1

c is the constant term => c = - 2

quadratic equation: [- b +/- √(b^2 - 4ac) ] / 2a =

= { 1 +/- √[ (-1)^2 - 4(1)(-2)] } / (2(1) = { 1 +/- √ (1 + 8) } / 2 = {1 +/- √9} / 2 =

= { 1 +/- 3} / 2
4 0
3 years ago
Please help i give brainliest
Marina86 [1]

Answer:

all FALSE except 3 and 4

Step-by-step explanation:

Hope this helps

6 0
2 years ago
Read 2 more answers
a boat can travel 30 miles upstream in the same amount of time you can travel 50 miles Downstream. If the speed of the current i
almond37 [142]
Speed, S = Distance (d) / Time (t) => S= d/t => t= d/S

Let the speed of boat in still water be x mph

Resulting speed upstream = x-4 mph for a distance of 30 miles
Resulting speed downstream = x-4 mph for a distance of 50 miles

Time taken in both distances is equal.
Therefore,

30/(x-4) = 50/(x+4) => 30(x+4) = 50(x-4) => 30x+120 = 50x-200 => 120+200 = (50-30)x => 20x = 320 => x=320/20 = 16 mph

The speed of boat in still water is 16 mph.


7 0
3 years ago
Read 2 more answers
The area of a tabletop is 48 square feet. the length is 3 times the width.if the dimensions are whole numbers, what is the width
posledela
(4 feet wide), 12 feet in length. 4*3=12    4*12=48
7 0
2 years ago
Other questions:
  • Factorise this equation
    11·1 answer
  • Given f(x) = (-1/7)(sqrt 16-x^2), find f^-1(x). Then state whether the inverse is a function.
    14·1 answer
  • I’ll give 17 points for this!
    9·2 answers
  • What come after 5,11,23,41,65,95,131 --- i will give brainly and points and thank you
    7·2 answers
  • What is the mean?<br> -1 -1 -4 -5 -4 -4 -7 -8
    9·1 answer
  • This rectangle represents the base of a rectangular prism. The height of the rectangular prism is 13 ft.
    10·2 answers
  • 6 times 10 to the power of -10 Normal numbers
    5·1 answer
  • I’ll give points + brainalist for he correct answer (:
    7·1 answer
  • How much fencing would need to enclose a circular pond with diameter 12.5 feet
    7·1 answer
  • i bougth 3 bags of candy and 1 drink for 3.20 dollars. my sister bought 2 bags of candy and 4 drinks for 6.30 dollars. how much
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!