What is the average velocity of an object that starts from rest and has a final velocity of 40 m/s?

The answer is b hope this

I'm having some difficulty seeing the diagram clearly.but the question says there's a net inward force on the object.so we know right away,  from newton's 2nd law of motion, thatthat baby is accelerating.  it doesn't even matter which way thenet force is pointing.  if there's any net force, then either theobject's speed or else its direction must be changing.

There was no intial y-momentum so the net final y-momentum must also be 0. they can have final velocities in the y-direction