1) In calculation of the average velocity V=s1suds in a circular pipe, uds is A XO) a volume rate element; B O) an area element; C O) a distance element; D O) a time element. 1. ds in above is AX O) an area element; B O) a volume element; CO) a time element; D O) a distance element 2. Mass flow rate is calculated by AO)m=su2ds;BXO)m=suds;CO)m=su3ds;DO)m=su4ds 3. Momentum flow rate element is A XO) u2ds; B O) uds; C O) ds;DO)u3ds 4. Kinetic energy rate element is A O) 0.5u2ds; B O) 0.5uds; C XO) 0.5u3ds;DO)0.5u4ds