1. A baseball is batted at an angle into the air. Once the ball is airborne, and neglecting air resistance, what is the ball’s acceleration vertically? Horizontally?
2. At what part of its trajectory does the baseball have minimum speed?
3. Consider a batted baseball following a parabolic path on a day when the Sun is directly overhead. How does the speed of the ball’s shadow across the field compare with the ball’s horizontal component of velocity?
1. Vertical acceleration is g because the force of gravity is vertical. Horizontal acceleration is zero because no horizontal force acts on the ball.
2. A ball’s minimum speed occurs at the top of its trajectory. If it is launched vertically, its speed at the top is zero. If launched at an angle, the vertical component of velocity is zero at the top, leaving only the horizontal component. So the speed at the top is equal to the horizontal component of the ball’s velocity at any point. Doesn’t this make sense?
3. They are the same!