1. In space ships, heat rejection to the surroundings is by radiation. A radiator in a space ship has an absorptivity αλ of 0.1 for 0 < λ < 2.5 µm, and 0.95 for λ > 2.5 µm. The surface is maintained at 600 K. What is the net heat flux from the surface when solar irradiation on the surface is 900 W/m2 ? Assume a sky temperature of 0 K, that the surface is diffuse and that the incident solar radiation is normal to the surface.

Explain the difference laminar and turbulent flow. explain it with the shear stress and the velocity profiles.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false

Afour cylinder four-stroke in-line engine has a stroke of 160mm, connecting rod length of 150mm, a reciprocating mass of 3kg and its firing order is 1-3-4-2. the spacing between cylinders is 100mm. i. show that the engine is in balance with regard to the primary inertia forces and primary 3. a and secondary inertia couples. li determine the out of balance secondary inertia force ii. propose ways of balancing this out of balance force and discuss the challenges that will arise