Someone throws a ball upward with an initial velocity of vi. use the free fall equations to determine and show the final velocity vf the ball has when it returns to the height from which it was released (hint you want a final equation that contains those two variables and no others). (further hint: what hidden information can you get from the phrase ""returns to the height from which it was released""? ) ignore air resistance.

so final velocity is same as initial velocity but its direction is opposite to the direction of initial velocity

Explanation:

As we know that when ball throw upwards and again reached to same position then we will have

so its displacement is zero

now by kinematics we will have

so we have

so we have

so final velocity is same as initial velocity but its direction is opposite to the direction of initial velocity

layer a is the exosphere and layer b is the thermosphere.   is the answer i think but i hope this .

the answer is b ) square root of 5