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1. A 100 g ice cube at -10?C is placed in an aluminum cup whose initial...

1. A 100 g ice cube at -10?C is placed in an aluminum cup whose initial temperature is 70?C. The system comes to an equilibrium temperature of 20?C. What is the mass of the cup in kg.

2.Radiation from the head is a major source of heat loss from the human body. Model a head as a 20-cm-diameter, 20-cm-tall cylinder with a flat top.If the body's surface temperature is 36 ?C , what is the net rate of heat loss in units W on a chilly 6 ?C day? All skin, regardless of color, is effectively black in the infrared where the radiation occurs, so use an emissivity of 0.97.

Solutions

Expert Solution

Heat lost by aluminium cup = Heat gained by ice cube

Mass of the aluminium cup is

--------------------------------

Rate of heat loss is

Given that, Radius of cylinder

Height of the cylinder

Temperature of body surface

Temperature of surroundings

Emissivity

Total area of cylinder (head ) where the heat is lost = Area of flat top+ Area of lateral surface

Heat loss from the head is

genius_generous answered 1 year ago

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