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Published byBaldric Simon Modified over 9 years ago
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Ex. 1 - A healthy person has an oral temperature of 98.6°F. What would be this reading on the Celsius scale?
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Ex. 2 - A time and temperature sign on a bank indicates the outdoor temperature is -20.0° C. Find the corresponding temperature on the Fahrenheit scale.
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The Kelvin temperature scale is 273.15 degrees above the Celsius scale. Zero in the Kelvin scale is absolute zero, the lowest attainable temperature.
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A thermometric property is a property that changes with temperature. A thermocouple - two wires of different metals are set at different temperatures at their junctions, producing a flow of electricity. The voltage is determined by the difference in temperature.
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Linear expansion - the increase in any one dimension of a solid. The change of length ∆L is determined by the change in temperature ∆T and the coefficient of linear expansion .
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∆L = L 0 ∆T The unit is 1/C° = (C°) -1
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Ex. 3 - A concrete sidewalk is constructed between two buildings on a day when the temperature is 25° C. The sidewalk consists of two slabs, each three meters in length and of negligible thickness. As the temperature rises to 38°C, the slabs expand, but no space is provided for thermal expansion. The slabs buckle upward. Determine the vertical distance the junction rises. ( for concrete is 12 x 10 -6 )
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Ex. 4 - A steel beam is used in the roadbed of a bridge. The beam is mounted between two concrete supports when the temperature is 23° C, with no room provided for thermal expansion. What compressional stress must the concrete supports apply to each end of the beam, if they are to keep the beam from expanding when the temperature rises to 42° C?
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A bimetallic strip is made by connecting two pieces of metal that have different coefficients of linear expansion. Changes in temperature cause this combination to bend when heated or cooled.
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A hole in a piece of solid material expands when heated and contracts when cooled, just as if it were filled with the material that surrounds it.
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Ex. 6 - A gold engagement ring has an inner diameter of 1.5 x 10 -2 m and a temperature of 27° C. The ring falls into a sink of hot water whose temperature is 49° C. What is the change in diameter of the hole in the ring?
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Ex. 7 - Three cylinders are all the same temperature, and barely fit inside each other. They are made of lead, brass, and steel. When heated to a higher temperature the outer cylinder falls off while the inner one becomes tightly wedges to the middle one. Which cylinder is made of which material?
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The volume of most materials increases as temperature increases by a factor called the coefficient of volume expansion . ∆V = V 0 ∆T The unit of is (C°) -1.
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Ex. 8 - A small plastic container catches the radiator fluid that overflows when an automobile engine becomes hot. The radiator is made of copper, and the coolant has a b = 410 x 10 -6 (C°) -1. If the radiator is filled to its 15-quart capacity when the engine is “cold” (6.0 °C), how much overflow from the radiator will spill into the reservoir when the coolant reaches its operating temperature of 92 °C?
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Water is unique in that at temperatures above, but close to, 0°C; it expands when cooled and contracts when heated. This only occurs between 0 and 4° C. As result, ice floats and provides an insulation to the water below. Therefore, lakes seldom freeze solid, a situation which benefits aquatic animals such as fish and Harry Houdini.
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Heat is energy that flows from a higher- temperature object to a lower-temperature object because of the difference in temperature.
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The internal energy of a substance is the sum of the molecular kinetic energy, the molecular potential energy, and other kinds of molecular energy.
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A substance does not contain heat; the term heat refers only to the transfer of energy from one substance to another.
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