Here's why:
* Gravity: When an object is thrown upwards, gravity constantly acts on it, slowing it down.
* Maximum Height: At the highest point of its trajectory, the object momentarily stops moving upwards before it starts falling back down.
* Speed vs. Velocity: While the object's speed is zero, its velocity is not. Velocity is a vector quantity, meaning it has both magnitude (speed) and direction. At the highest point, the object's velocity is momentarily zero, but its direction is still changing (from upwards to downwards).
