A 1600-kg automobile traveling at 55 mph brakes smoothly to a stop. Assume 40% of the heat generated in stopping the car is dissipated in the front steel brake disks. Each front disk has a mass of 3.0 kg. What is the temperature rise of the front brake disks during the stop?
Answer to relevant QuestionsA waterfall is 75 m high. If of the gravitational potential energy of the water went into heating the water, by how much would the temperature of the water, increase in going from the top of the falls to the bottom? A 5.00-g pellet of aluminum reaches a final temperature of 63 oC when gaining 200 J of heat. What is its initial temperature? If heat engine A absorbs more heat than heat engine B from a hot reservoir, will engine A necessarily do more net work than engine B? Explain your reasoning. A fixed quantity of gas undergoes the reversible changes illustrated in the p–V diagram in Fig. 12.22. How much work is done in each process? What is the change in entropy of mercury vapor (Lv = 2.7 x 105 J/kg) when 0.50 kg of it condenses to a liquid at its boiling point of 357 oC?
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