Select the most economical W section of 50ksi steel for a 40 ft simple beam that supports a service concentrated load PL=30k at the midspan is laterally unbraced except at its ends and center line. If the maximum permissible center line deflection is 1/1000 of the span. Neglect beam weight.

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

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

Which of the following ziegler nichols tuning methods the response of the controller to a step input should exhibit an s-shaped curve? a)-open loop mode b)-closed loop mode c)-both modes (open & closed) d)-none of the modes (open & closed)