If you wish to warm 150 kg of water by 20°C for your bath, show that the amount of heat needed is 3000 kcal (3000 Cal, more than the amount of food energy the average human needs per day!). Then show that this is equivalent to about 12,600 kJ.

If you wish to warm 150 kg of water by 20°C for your bath, show that the amount of heat needed is 3000 kcal (3000 Cal, more than the amount of food energy the average human needs per day!). Then show that this is equivalent to about 12,600 kJ.

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

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Imagine a swimming pool 25 m long and 15 m wide. If the water is exactly 2 m deep when the water temperature is 20 ° C, how deep will the water be if the temperature increases to 21 ° C?
Bebang owns a 230-mm-thick concrete brick table top that has an area of 10,000,000 mm^2 and a 0.050-cm-thick glass plate that has an area of 20,000 cm^2. Assuming the same temperature difference across each, what is the ratio of the rate of heat conduction through the plate with respect to the rate of heat conduction through the table top? Use Table 10.1(given below) for the value of Thermal Conductivity k. Table 10.1 Thermal Conductivities of Common Substances Values are given for temperatures near 0 °C. Substance Diamond Silver Copper Gold Aluminum Steel iron Steel (stainless) ke Glass (average) Concrete brick Water Fatty tissue (without blood) Asbestos Plasterboard Wood Snow (dry) Cork Glass wool Wool Down feathers Air Polystyrene foam Thermal Conductivity k (W/m-C) 2000 420 390 318 220 80 14 2.2 0.84 0.84 0.6 0.2 0.16 0.16 0.08-0.16 0.10 0.042 0.042 0.04 0.025 0.023 0.010
A thermometer reading 5°C is brought into a room with a constant temperature of 29°C. If the thermometer reads 14°C after 3 minutes, what will it read after being in the room for 5 minutes? For 10 minutes? After 5 minutes, the thermometer will read°C. (Do not round until the final answer. Then round to the nearest hundredth as needed.)
The recommended daily caloric intake is 2000 calories (8,400,000J). This is because this is the same value for how much the average body loses to heat and work in a typical day (your change in energy is zero because you take in the same amount of energy you lose). A) If you lose a total of 8,400,000J (Qout+W=total lost), but consume 1200 calories of food (5,000,000J), what would your change in energy be? B) Assuming your change in energy is negative (hint-it should be), where does your body get the extra energy to maintain it's temperature?
A very hot piece of iron is placed in 200 mL of water. The water is initially at 20°C and heats up to 37 C. Remembering that water has a specific heat of 1 cal/(g* C), how much heat did the water gain? Q = %3D unit The iron had a mass of 290 grams. Iron has a specific heat of .11 cal/(g*° C). Assuming that iron lost all of the heat the water gained and also reached a final temperature of 37 ° C, what was its initial temperature? T = unit ?
When you turn your hot water on in the shower, it takes a bit for the water to get warm. Some of this is because the water in the pipe is cold but some of it is because the water from the hot water heater must heat the copper plumbing pipe itself. Copper has a specific heat of 0.39R. How much energy does it take to heat 2 kilograms of copper pipe from 70°F to 130°F? Report your answer in Joules. (Hint: Note that you'll need to convert kJ to J and F to K.)
How much energy in kJ is needed to raise the 12 kg of now gaseous nitrogen N, from boiling temperature, -196 °C, to room temperature, 20°C.? The specific heat of nitrogen gas is is c = 1,004 Joules/kg°C.
How much radiant energy is emitted by one square meter of an object (a) at 77K (b) 300K and (c) 2000K? 1
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