Let L1, L2 are regular and L3, L4 are context free grammar. Whether the following is true or false. For each, prove your answer. (You can use counter example if
necessary)
a) L1 ∪ L2 is regular.
b) L1 ∩ L2 is regular.
c) L3 ∪ L4 is context free.
d) L3 ∩ L4 is context free

An electrical motor raises a 50kg load at a construct velencity .calculate the power of the motor, if it takes 40sec to raise the load through a height of 24m(take g =9.8n/g)

Water at 70°f and streams enter the mixing chamber at the same mass flow rate, determine the temperature and the quality of the exiting stream. 0 psia is heated in a chamber by mixing it with saturated water vapor at 20 psia. if both streams enters the mixing chamber at the same mass flow rate, determine the temperature and the quality of the existing system.

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.