Based on the principles of convection, conduction and thermal radiation, which scenario below is most similar to the following situation? You put a heating pad on your back after exercising.
Question 20 options:

Feeling a metal wire get warmer as you roast a marshmallow over a fire.

Warm air rising in a room where the air is moving.

The sun warming up the roof on a house.

Cold water sinking in a pot of water being warmed up on the stove.
Question 21 (1 point)

Determine whether or not it is possible to compress air adiabatically from k to 140 kpa and 400 k. what is the entropy change during this process?

How much power could a wind turbine produce if it had the following specifications? cp = 0.45 -d=1.2kg/m3 d=50m v 5m/s

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.