Chapter 1, Problem 1.66P

An electric heater producing 260 W of heat is used to warm up a room containing 7 m3 of air. If we assume the room is perfectly sealed and there is no heat loss through the room boundaries, such that all of the heater output goes into increasing the air temperature, how long will it take to heat up the air in the room from 5.0 °C to 24.1 °C? Give your answer to the nearest minute and assume that the specific volume (v = 0.85 m3/kg) and specific heat capacity at constant volume (cv = 1.005 kJ/(kg K)) remain constant throughout the heating process.

What happens to heat transfer per unit time in conduction heat transfer as thermal conductivity decreases?

Determine the heat conduction of a boiler if you are given the following data: The thickness of the boiler is 15 cm, the T1 is the temperature of the water is 25°C and the T2 of the steam is 110°C, the thermal conductivity The boiler material is iron (use presentation table), the boiler area is 4.5 m^2

is |Q|=-kA(dt/dx) the law that defines the rate of heat transfer by conduction (fourier's law of heat conduction) or is it |Q| = hA(tb-Tf)?

1.77 Explain each in your own words. (a) What is the mode of heat transfer through a large steel plate that has its surfaces at specified temperatures? (b) What are the modes when the temperature on one surface of the steel plate is not specified, but the surface is exposed to a fluid at a specified temperature?

EXPERIMENT PROBLEM: A certain mechanical device with a mechanism similar to a piston contains a certain amount of gas. Upon compression from 55 L to 15 L, the gas released 350 J of heat. Experiment shows that the external pressure of the mechanical device is given by: Pext = AsinV + BcosV + CsinhV + DcoshV Where: A = 100 B = 80 C = 1x10⁻²⁵ D = 5x10⁻³⁰ sin = sine function cos = cosine function sinh = hyperbolic sine function cosh = hyperbolic cosine function V = in liters Pext = in atm Determine the change in internal energy of the system in kilojoules. TIP: usually, expressions involving trigonometric functions are in radians.

Surface quality is affected due to Resistance strength of contact surfaces Friction resistance of contact surfaces O strength of joint contact surfaces O Wear resistance of contact surfaces

A pot with a diameter of 20 cm is placed on the stove. The pot is made of stainless plate (k = 15 W / [m ° C]), and contains boiling water at 98 ° C. The bottom of the pan is 0.4 cm thick. The surface temperature in the bottom of the pan in contact with water is 105 ° C. a. If the heat transfer rate through the bottom of the pan is 600 W, determine the temperature of the outside surface of the pan that is exposed to the heating stove. = Answer ° C. b. Find the convective heat transfer coefficient of boiling water = AnswerW / m2 ° C

A pot with a diameter of 20 cm is placed on the stove. The pot is made of stainless plate (k = 15 W / [m ° C]), and contains boiling water at 98 ° C. The bottom of the pan is 0.4 cm thick. The surface temperature in the bottom of the pan in contact with water is 105 ° C. a. If the heat transfer rate through the bottom of the pan is 500 W, determine the temperature of the outside surface of the pan that is exposed to the heating stove. = Answer ° C. b. Determine the convective heat transfer coefficient of boiling water = Answer W / m2 ° C