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Ann [662]
3 years ago
7

A 403.0-kg copper bar is melted in a smelter. The initial temperature of the copper is 320.0 K. How much heat must the smelter p

roduce to completely melt the copper bar? For solid copper, the specific heat is 386 J/kg • K, the heat of fusion is 205 kJ/kg, and the melting point is 1357 K.
Physics
2 answers:
Liono4ka [1.6K]3 years ago
8 0

Answer:

2.42 x 10^8 J

Explanation:

m = 403 kg

T1 = 320 K

c = 386 J/Kg C

L = 205 kJ / kg = 205000 J/Kg

T2 = 1357 K

Heat used to increase the temperature till 1357 K

H1 = m x c x (T2 - T1)

H1 = 403 x 386 x ( 1357 - 320)

H1 = 1.6 x 10^8 J

Heat used to melt

H2 = m x L

H2 = 403 x 205000 = 8.2 x 10^7 J

Total heat used to melt completely

H = H1 + H2

H = 1.6 x 10^8 + 0.82 x 10^8 = 2.42 x 10^8 J

aleksklad [387]3 years ago
7 0
The answer is 2.49 x 10^5 KJ. This was obtained (1) use the formula for specific heat to achieve Q or heat then (2) get the energy to melt the copper lastly (3) Subtract both work and the total energy required to completely melt the copper bar is achieved.
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Answer:

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You have a summer job at a company that developed systems to safely lower large loads down ramps. Your team is investigating a m
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Answer:

Note that the emf induced is

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where

B = magnetic field

d = distance of two rails

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A = angle of rails with respect to the horizontal

Also, note that

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Thus, the component of this parallel to the incline is

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As this is equal to the component of the weight parallel to the incline,

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where m = the mass of the bar.

Solving for v,

v = [R m g sin (A) / B^2 d^2 cos^2 (A)]   [ANSWER, the constant speed, PART A]

******************************

v = [R m g sin (A) / B^2 d^2 cos^2 (A)]

Plugging in the units,

m/s = [ [ohm * kg * m/s^2] / [T^2 m^2] ]

Note that T = kg / (s * C), and ohm = J * s/C^2

Thus,

m/s = [ [J * s/C^2 * kg * m/s^2] / [(kg / (s * C))^2 m^2] ]

= [ [J * s/C^2 * kg * m/s^2] / [(kg^2 m^2) / (s^2 C^2)]

As J = kg*m^2/s^2, cancelling C^2,,

= [ [kg*m^2/s^2 * s * kg * m/s^2] / [(kg^2 m^2) / (s^2)]

Cancelling kg^2,

= [ [m^2/s^2 * s * m/s^2] / [(m^2) / (s^2)]

Cancelling m^2/s^2,

= [s * m/s^2]

Cancelling s,

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shusha [124]

Answer:

1.6\times 10^{-18} C  

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Answer:

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