1: mcq thinking method
KE new = (1/2)mv^(2) *3
in here "m" is constant & "1/2" also constant . since v^(2) increases from thrice.
Hence v increases from 3^(1/2). which is the same with mv!
ans : 73% ( i.e.: because answer has asked just the increasing percentage of the mv!
2: more...