Abaseball is dropped off the side of a cliff. it free-falls to the ground in 8 seconds. during the third second, the ball is traveling about m/s.

The acceleration of gravity is 9.8 m/s² .  That means that a falling object
is always falling 9.8 m/s faster than it was falling 1 second earlier.

If an object is not slowed by air resistance, and has far enough to go
so that it's still falling after three whole seconds, then at the end of
three seconds it's falling at

           (9.8 m/s²) x (3 sec)  =  29.4 m/s

26.4 is about the right time