Physics equations/14-Heat and Heat Transfer/Q:SpecificHeatEnergyConductivity

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A

1

The specific heat of water and aluminum are 4186 and 900, respectively, where the units are J/kg/Celsius. An aluminum container of mass 0.98 kg is filled with 0.23 kg of water. How much heat does it take to raise both from 39.7 C to 88 C?

	a) 8.91 x 104 J
	b) 1.05 x 105 J
	c) 1.24 x 105 J
	d) 1.46 x 105 J
	e) 1.72 x 105 J

2

Referring to the previous question, what fraction of the heat went into the aluminum?

	a) 2.9 x 10-1
	b) 3.4 x 10-1
	c) 4.1 x 10-1
	d) 4.8 x 10-1
	e) 5.6 x 10-1

3

Referring to the previous question, you are presenting this idea to the flat earth society, a group of people who believe that the acceleration of gravity equals 9.8 m/s/s at all altitudes. Based on this assumption, from what height must the water and container be dropped to achieve the same change in temperature? (For comparison, Earth's radius is 6,371 kilometers)

	a) 5.12 x 100 km
	b) 6.2 x 100 km
	c) 7.51 x 100 km
	d) 9.1 x 100 km
	e) 1.1 x 101 km

4

A window is square, with a length of each side equal to 0.86 meters. The glass has a thickness of 14 mm. To decrease the heat loss, you reduce the size of the window by decreasing the length of each side by a factor of 1.46. You also increase the thickness of the glass by a factor of 2.31. If the inside and outside temperatures are unchanged, by what factor have you decreased the heat flow?. By what factor have you decreased the heat flow (assuming the same inside and outside temperatures).

	a) 4.06 x 100 unit
	b) 4.92 x 100 unit
	c) 5.97 x 100 unit
	d) 7.23 x 100 unit
	e) 8.76 x 100 unit