Final answer:
Yes, velocity can increase while acceleration decreases, as seen in projectile motion. Average velocity can be negative if displacement is in the negative direction. Changes in direction, even at constant speed, indicate a change in velocity, and objects in uniform circular motion are accelerating because their direction changes.
Step-by-step explanation:
The answer is yes, velocity can indeed increase while acceleration decreases. This scenario may seem counterintuitive, but it occurs in specific cases such as an object in projectile motion after it passes its peak and starts to fall back down. The acceleration, due to gravity, remains constant, but as the object has reached its maximum height and begins descending, its vertical velocity increases until it hits the ground, even though the acceleration due to gravity (a downward force) does not change.
Now, addressing the additional questions:
- Is it possible for average velocity to be negative? Yes, this can occur when the net displacement is towards the negative direction.
- Is there a change in velocity if an object turns a corner at a constant speed? Yes, because velocity is a vector, hence a change in direction implies a change in velocity.
- Is an object in uniform circular motion accelerating? Yes, because even though its speed may be constant, its direction is constantly changing, which constitutes a change in velocity.