You throw a baseball straight up at 40 m/s and it reaches its peak after 4.00 seconds. What is its speed when it falls back into your hand? What is its displacement? What distance has it traveled?
Because of the symmetry in the path of a projectile, it will return to your hand with a speed of 40 m/s downward. Its total displacement is 0 since it returns to starting position.
To find the distance traveled, multiply the height it reaches by 2. Find the height using kinematic equation:
V^2 = V0^2-2gy
where y = h and and V^2 =0 because velocity is 0 at the top of its path.