13.If a jet plane with a velocity of 20 m/s at t = 0 accelerates at a rate of 40 m/s² for 3 seconds, what is its veloaty at time = 3 seconds?​

Three-phase, 4-wire panelboards are usually constructed with an even number ofspaces available for each phase; thus, the total number of spaces would be in incre-ments of 6, such as 12, 18, 24, 30, 36, or 42. how many spaces would be available forthe later addition of circuit breakers in panelboard p-1 after the panelboard has been equipped as scheduled?