Pls explain the following

f=v dm/dt
=v(_av)
=_av^2

what is the 2nd v in the bracket? ? where does it come from? ?

(1 point) match the differential equations and their vector valued function solutions. you may wish to multiply at least one solution out fully, to make sure that you know how to do it. you can get the other answers quickly by process of elimination and just multiply out one row element.