a. 0 m/s
b. 9.8 m/s squared
the velocity of the ball at its maximum height would be zero. this is because at its highest point, the ball would stop moving for a second before it goes back to the ground.
right before the ball hits the ground, it would have an acceleration of 9.8 m/s squared. this is the speed of gravity so this the rate all objects fall at.
