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
In-s [12.5K]
3 years ago
12

A solid cylindrical bar conducts heat at a rate of 25 W from a hot to a cold reservoir under steady state conditions. If both th

e length and the diameter of this bar are doubled, the rate at which it will conduct heat between these reservoirs will be
Physics
1 answer:
expeople1 [14]3 years ago
7 0

Answer:

Using the new cylinder the heat rate between the reservoirs would be 50 W

Explanation:

  1. Conduction could be described by the Law of Fourierin the form: Q=kA\frac{T_1-T_2}{L} where Q is the rate of heat transferred  by conduction, k is the thermal conductivity of the material, T_1 and T_2 are the temperatures of each heat deposit, A is the cross area to the flow of heat, and {L} is the distance that the flow of heat has to go.
  2. For the original cylinder the Fourier's law would be: kA_1\frac{T_1-T_2}{L_1}=25W, and if A_1=\frac{\pi D_{1}^{2}}{4}, then the expression would be:k\frac{\pi D_1^{2}}{4} \frac{T_1-T_2}{L_1}=25W where D_1 is the diameter of the original cylinder, and {L_1} is the length of the original cylinder.
  3. For the new cylinder, in the same fashion that for the first, Fourier's Law would be: Q_2=k\frac{\pi D_2^2}{4}\frac{T_1-T_2}{L_2},where Q_2 is the heat rate in the second case, D_2 and {L_2 are the new diameter and length.
  4. But, D_2=2D_1 and L_2=2L_1, substituting in the expression for Q_2: Q_2=k\frac{\pi (2D_1)^2}{4}\frac{T_1-T_2}{2L_1}.
  5. Rearranging: Q_2=\frac{2^2}{2}(k\frac{\pi D_1^2}{4}\frac{T_1-T_2}{L_1}).
  6. In the last declaration of  Q_2, it could be noted that the expressión inside the parenthesis is actually  Q_1, then:  Q_2=\frac{2^2}{2}(25W)=50W.
  7. <u>It should be noted, that the temperatures in the hot and cold reservoirs never change.</u>
You might be interested in
A physics student spends part of her day walking between classes or for recreation, during which time she expends energy at an a
kondor19780726 [428]
RESULT: Twalk= 3.64 hr

7 0
2 years ago
What does popular sovereignty
Lana71 [14]

I'm a little confused by your question.

If you mean what is popular sovereignty, it is the belief that the governments is made and sustained by the consent of the people that it governs.

6 0
3 years ago
______ creates heat in earths interior when dense substance sink into earths core.
anastassius [24]

The answer is A. Friction

hope this helps :)

7 0
3 years ago
~ is the following statement true or false? Explain your answer.
USPshnik [31]

Answer: False

Explanation: The sun is one of earths primary energy sources. Without the sun, all animals, plants, humans would die. The sun's energy provides warmth for humans and plants and animals cannot grow without the sun.

7 0
2 years ago
What distance will be traveled if you are going 120km/hr for 0.75 hr?
SVEN [57.7K]

Answer:

60 km

Explanation:

For an object (or a person, such as in this case) moving at constant speed, the speed is equal to the ratio between the distance travelled and the time taken:

where

v is the speed

d is the distance

t is the time taken

In this case, we have:

v = 120 km/h is the speed

t = 30 min = 0.5 h is the time taken

Therefore, we can rearrange the equation to find the total distance travelled:

5 0
3 years ago
Other questions:
  • A solenoid 2.5 cm in diameter and 30 cm in length has 4800 turns and carries a current of 2.0 A. Part A Calculate the magnetic f
    13·1 answer
  • Taylor drives 5 miles in 10 minutes. She stops at a light for 2 minutes. She then travels another 10 miles in 8 minutes. What wa
    14·1 answer
  • A cannonball of mass 15 kg is fired vertically upward from a cannon with an initial speed of 20 m/s. The cannonball travels upwa
    6·1 answer
  • Which of the following is true about natural selection?
    9·1 answer
  • angie is moving a couch with a mass of 48 kg. she moves it in 120 seconds using 240 j of work. what is her power output
    10·1 answer
  • A 94 g particle undergoes SHM with an amplitude of 8.3 mm, a maximum acceleration of magnitude 7.8 x 103 m/s2, and an unknown ph
    11·1 answer
  • What items resemble the path of light when it travels through space?
    9·1 answer
  • 1.
    9·1 answer
  • All fires require oxygen () There is no oxygen in that room (T) .
    8·1 answer
  • Is language an innate or an acquired one
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!