A 3m2 black surface at 140 oC is losing heat to the surrounding air at 35oC by convection with a heat transfer coefficient of 16W/m2K and by radiation to the surrounding surfaces at 15oC. What is the total rate of heat loss from the surface? (a) 1987 W
(b) 2239 W
(c) 2348 W
(d) 3451 W
(e) 3811 W

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

The drive force for diffusion is 7 fick's first law can be used to solve the non-steady state diffusion. a)-true b)-false