Understanding Velocity and Acceleration

* Velocity: Describes how fast an object is moving and in what direction. It's a vector quantity.

* Acceleration: Describes the rate of change of velocity. It's also a vector quantity, meaning it has both magnitude (how much) and direction.

The Scenario

Imagine a ball thrown straight up into the air.

* At the highest point: The ball momentarily stops moving (zero velocity).

* However: Gravity is still acting on it, pulling it downwards. This means the ball is still accelerating downwards even though it's not moving at that instant.

Another Example

A car at a stoplight. The car is not moving (zero velocity) but the driver has their foot on the brake. The brake is applying a force, causing an acceleration (in this case, deceleration) to keep the car from moving.

In Summary

A particle can have zero velocity and non-zero acceleration when a force is acting upon it, causing its velocity to change. This change in velocity, even if it's from a stationary position, is acceleration.