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laila [671]
3 years ago
12

The ends of a cylindrical steel rod are maintained at two different temperatures. The rod conducts heat from one end to the othe

r at a rate of 10 cal/s. At what rate would a steel rod twice as long and twice the diameter conduct heat between the same two temperatures?
Physics
1 answer:
Olenka [21]3 years ago
7 0

Answer:20 cal/s

Explanation:

Given

Heat transfer rate is \dot{Q}=10 cal/s

Also heat rate is given by

\dot{Q}=kA\frac{dT}{dx}

where k=thermal\ conductivity

A=area\ of\ cross-section

dT=change\ in\ temperature

dx=change\ in\ length

10=k\frac{\pi }{4}d^2\frac{dT}{L}----1

For d'=2d, Length L'=2L

\dot{Q}=k\frac{\pi }{4}(2d)^2\frac{dT}{2L}---2

dividing 1 and 2 we get

\frac{10}{\dot{Q}}=\frac{2d^2}{4d^2}

\dot{Q}=20 cal/s                            

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under ground cave will be created


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Given that coal used by electric power plants has a heating value of 27.5 million btus metric ton (25 million btus per ton), det
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Answer:

• 36.4 kg of coal.

• 80 pounds of coal.

Explanation:

Using proportionality constant,

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Converting metric tons to kilogram,

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3 0
3 years ago
A roller coaster cart of mass m = 223 kg starts stationary at point A, where h1 = 26.8 m and a while later is at B, were h2 = 14
Tresset [83]

Answer:

vB = 15.4 m/s

Explanation:

Principle of conservation of energy:

Because there is no friction the mechanical energy is conserve

ΔE = 0

ΔE : mechanical energy change (J)

K : Kinetic energy (J)

U: Potential energy (J)

K = (1/2)mv²

U = m*g*h

Where :

m: mass (kg)

v : speed (m/s)

h : hight (m)

Ef - Ei = 0

(K+U)final - (K+U)initial =0

(K+U)final = (K+U)initial

((1/2)mv²+m*g*h)final = ((1/2)mv²+m*g*h)initial , We divided by m both sides of the equation:

((1/2)vB² + g*hB = (1/2 )vA²+ g*hA

(1/2) (vB)² + (9.8)*(14.7) =  0 + (9.8)(26.8 )

(1/2) (vB)² = (9.8)(26.8 ) - (9.8)*(14.7)

(vB)² = (2)(9.8)(26.8 - 14.7)

(vB)² = 237.16

v_{B} = \sqrt{237.16}

vB = 15.4 m/s : speed of the cart at B

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3 years ago
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