When a ball is thrown vertically upward, it is constantly decelerating due to the force of gravity acting downwards. As it travels upwards, its speed decreases. At the very peak of its trajectory, just for an instant before it begins to fall back down, its instantaneous vertical velocity is Zero. This is the turning point where its direction of motion reverses.
- Constant velocity would imply no acceleration, which is incorrect under gravity.
- Maximum velocity occurs at the moment it is thrown, not at the highest point.
- Minimum velocity is indeed zero, but 'zero' is the precise value at the highest point.