* Gravity is constant: The primary force acting on a projectile throughout its flight is gravity. Gravity pulls the projectile downwards with a constant acceleration of approximately 9.8 m/s².
* Velocity vs. Acceleration: While the projectile's vertical velocity is zero at its peak (it momentarily stops going up before coming down), its acceleration is still constant and downward due to gravity.
Think of it this way:
* At the peak: The projectile has stopped moving upward, but gravity is still pulling it down. This downward pull is what causes the projectile to start descending.
* Acceleration is about change in velocity: Even though the vertical velocity is zero at the peak, the projectile is still experiencing a change in velocity (from going up to going down). This change in velocity is what defines acceleration.
In summary: A projectile's acceleration at its peak is not zero. It's still experiencing the constant downward acceleration due to gravity.
