Achild drops a ball from a window. the ball strikes the ground in 3.0seconds. what is the velocity if the ball the instant before it hits the ground

Explanation:

As we know that the ball is dropped from rest

So here we know acceleration of the object is due to gravity

So we will have

now we have

here we have

now from above equation we have

i think its

grav force prop 1/r squared 2r all squared is 4rsquared 1/4rsquared quartered