A baseball is thrown straight up with initial speed v(o). If air resistance cannot be ignored, when the ball returns to its initial height its speed is less than v(o). Explain why, using energy concepts. I am very confused as to why this is. A projectile has the same initial kinetic energy no matter what the angle of projection. Why doesn't it rise to the same maximum height in each case? Is it because the velocity in the x-direction is different?