Final answer:
When a stone is thrown vertically upward, it undergoes free-fall motion with decreasing velocity until it reaches its highest point, and then falls back down with increasing velocity.
Step-by-step explanation:
When a stone is thrown vertically upward, it undergoes a specific type of motion called free-fall motion. Free-fall motion occurs when an object is under the influence of gravity and experiences constant acceleration. In this case, the stone is thrown with an initial velocity upward, and as it moves against gravity, its velocity decreases until it reaches its highest point and then starts falling back down.
During the upward motion, the stone's velocity decreases uniformly, while its acceleration remains constant. At the highest point, the stone's velocity is zero and its acceleration is equal to the acceleration due to gravity, which is approximately 9.8 m/s². As the stone falls back down, its velocity increases in the opposite direction until it hits the ground.
For example, if a stone is thrown upward with an initial velocity of 20 m/s, it will reach its highest point when its velocity becomes zero, and then fall back down to the ground with an increasing velocity. The motion of the stone can be represented by a position-time graph, which would show a parabolic shape.