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
Ghella [55]
3 years ago
14

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

mperature and that of its surroundings. Suppose that the temperature of a cup of coffee obeys Newton's law of cooling. If the coffee has a temperature of 185 degrees Fahrenheit when freshly poured, and 3 minutes later has cooled to 172 degrees in a room at 78 degrees, determine when the coffee reaches a temperature of 147 degrees.
Physics
1 answer:
schepotkina [342]3 years ago
4 0

Answer:

6.77 minutes

Explanation:

172 degree - 78 degree = (185 degree - 78 degree)e−2 k

=> 94 = 107

e−2 k => 94 ÷ 107

k => ln (94÷107) / 2

147 - 78 = (185 - 78)e ^[ln (94÷107) / 2]

=> 69 = 107 e^ [ln (94÷107) / 2]

e^[ln (94÷107) / 2] =69 ÷ 107

=> t = [ln (69 ÷ 107)] ÷ [ln (94÷107) / 2]

t=> -0.4387 ÷ -0.0648

t => 6.77 minutes.

Therefore, the final answer to the question is 6.77 minutes.

You might be interested in
If two monochromatic light waves undergo destructive interference, the amplitude of the resultant wave is
lesya692 [45]

Answer: The amplitude is 0. (assuming that the amplitude ot both initial waves is the same)

Explanation:

When two monochromatic light waves of the same wavelength and same amplitude undergo destructive interference, means that the peak of one of the waves coincides with the trough of the other, so the waves "cancel" each other in that point in space.

Then if two light waves undergo destructive interference, the amplitude of the resultant wave in that particular point is 0.

5 0
3 years ago
Read 2 more answers
2.0 mol of monatomic gas A initially has 5000 J of thermal energy. It interacts with 3.0 mol of monatomic gas B, which initially
Naddika [18.5K]

Answer:

 E_particle = 1,129 10⁻²⁰ J / particle

  T= 817.5 K

Explanation:

Energy is a scalar quantity so it is additive, let's look for the total energy of each gas

Gas a

         E_a = 2 5000 = 10000 J

Gas b

         E_b = 3 8000 = 24000 J

When the total system energy is mixed it is

          E_total = E_a + E_b

          E_total = 10000 + 24000 = 34000

The total mass is

           M = m_a + m_b

           M = 2 +3 = 5

The average energy among the entire mass is

           E_averge = E_total / M

            E_averago = 34000/5

            E_average = 6800 J

One mole of matter has Avogadro's number of atoms 6,022 10²³ particles

Therefore, each particle has an energy of

                E_particle = E_averag / 6.022 10²³ = 6800 /6.022 10²³

                E_particle = 1,129 10⁻²⁰ J / particle

For  find the temperature let's use equation

               E = kT

               T = E / k

     

               T = 1,129 10⁻²⁰ / 1,381 10⁻²³

               T = 8.175 102 K

               T= 817.5 K

5 0
3 years ago
can someone describe how someone is moving-- have examples of positive velocity negative velocity and acceleration and the perso
Rama09 [41]

Assume the motion when you are in the car or in the school bus to go to the school.


To describe the motion the first thing you need is a point of reference. Assume this is your house.


This should be a description:

  • When you are sitting and the car has not started to move you are at rest.
  • The car starts moving from rest, gaining speed, accelerating. You start to move away from your house, with a positive velocity (from you house to your school) and positive acceleration (velocity increases).
  • The car reaches a limit speed of 40mph, and then moves at constant speed. The motion is uniform, the velocity is constant, positive, since you move in the same direction), and the acceleration is zero.
  • When the car approaches the school, the driver starts to slow down. Then, you speed is lower but yet the velocity is positive, as you are going in the same direction. The acceleration is negative because it is in the opposite direction of the motion.
  • When the car stops, you are again at rest: zero velocity and zero acceleration.
  • In all the path your velocity was positive, constant at times (zero acceleration) and variable at others (accelerating or decelerating).
  • When you comeback home, then you can start to compute negative velocities, as you will be decreasing the distance from your point of reference (your house).


4 0
3 years ago
You are an electrician installing the wiring in a new home. The homeowner desires that a ceiling fan with light kits be installe
In-s [12.5K]

Answer:

3 fans per 15 A circuit

Explanation:

From the question and the data given, the light load let fan would have been

(60 * 4)/120 = 240/120 = 2 A.

Next, we add the current of the fan motor to it, so,

2 A + 1.8 A = 3.8 A.

Since the devices are continuos duty and the circuit current must be limited to 80%, then the Breaker load max would be

0.8 * 15 A = 12 A.

Now, we can get the number if fans, which will be

12 A/ 3.8 A = 3.16 fans, or approximately, 3 fans per 15 A circuit.

8 0
3 years ago
A net force is applied on a 100 kg rocket which causes the rocket to acceleration at 10 m/s2. The same net force is applied on a
ELEN [110]

Answer:

i dont know lo

Explanation:

8 0
2 years ago
Other questions:
  • Arden is making a pros and cons list about genetic engineering for a debate at school. Which part of her list is incorrect?
    14·2 answers
  • A 200-kg object has a 50-Newton rightward net force being applied to it. What is the magnitude of the rightward acceleration on
    10·1 answer
  • The maximum pressure achieved during ventricular contraction is called
    13·2 answers
  • If a truck is travelling east on a straight road and travels 100 meters in 25s what is the truck's velocity?
    8·1 answer
  • An optical fiber is made of clear plastic (n = 1.50). Light travels through the fiber at angles ranging from 40° to 55°. What is
    12·1 answer
  • What is the result of convection currents in the atmosphere?
    13·1 answer
  • The focused, penetrating sound of the koto, which is similar to the tone of Japanese vocal music, comes from the_______________
    7·1 answer
  • A 500 500500- kg kgstart text, k, g, end text object is accelerating to the right at 10 cm / s 2 10 cm/s 2 10, start text, space
    8·2 answers
  • In the sum of 4.34 + 5.66, the number of significant figures is
    15·1 answer
  • -4, 0, -2/3, 4.11111…, 2, π, √6 'which members of this set are irrartional?
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!