1. A large opaque plate has a top surface temperature Ts = 150.1 ◦C and is insulated on the bottom side. The top of the plate emits E" = 1090 W m2 and is exposed to air T[infinity] = 195.45◦C with a convective heat transfer coefficient h = 15 W m2·K . Incident to the plate is irradiation G" = 2000 W m2 , of which 1200 W m2 is reflected. (a) Determine the emissivity, absorptivity, reflectivity, and radiosity (in W m2 ) of the plate. (b) Does the plate behave as a gray surface? (c) Determine the net heat flux q 00 (in W m2 ). Specify if this is into or out of the plate. Answer : q 00 net = 390 W m2

When at a point two solid phase changes to one solid phase on cooling then it is known as a) eutectoid point b) eutectic point c) peritectic point d) peritectoid point

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

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