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Author Question: Star A has a radius of 200 000 km and a surface temperature of 6 000 K. Star B has a radius of 400 ... (Read 99 times)

armygirl

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on: Jul 28, 2018
Star A has a radius of 200 000 km and a surface temperature of 6 000 K. Star B has a radius of 400 000 km and a surface temperature of 3 000 K. The emissivity of both stars is the same. What is the ratio of the rate of energy radiated by Star A to that of Star B?

Question 2

In braking an automobile, the friction between the brake drums and brake shoes converts the car's kinetic energy into heat. If a 1 500-kg automobile traveling at 30 m/s brakes to a halt, how much does the temperature rise in each of the four 8.0-kg brake drums? (The specific heat of each iron brake drum is 448 J/kg/C).


ally

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Reply #1 on: Jul 28, 2018
Answer to Question 1

4

Answer to Question 2

47C


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