You throw a ball upward and then it falls back down. How does the velocity of the ball change as it rises and falls?
The velocity of the ball changes as it rises and falls in a predictable manner due to the force of gravity. To understand this, we need to consider two main factors: the acceleration due to gravity and the direction of motion.
When you throw the ball upward, initially its velocity is positive in the upward direction. As the ball moves against the force of gravity, its velocity decreases or becomes less positive. Eventually, at the highest point of its trajectory (known as the apex), the ball's velocity reaches zero. This is because gravity slows down the ball's upward motion, causing it to momentarily come to a stop before it starts descending.
As the ball falls back down, its velocity begins to increase again but in the opposite direction. It becomes more negative as it accelerates downwards due to the force of gravity. At any point during the fall, the velocity of the ball will always be negative (assuming upward is considered the positive direction) because it is moving downwards.
In summary:
- As the ball rises, its velocity decreases from positive to zero.
- At the apex, the ball's velocity is zero.
- As the ball falls, its velocity increases from zero to negative.
This change in velocity during both ascent and descent is due to the influence of gravity on the object.