Velocity and acceleration are fundamental concepts in physics that describe the motion of objects and how that motion changes over time.  Velocity refers to not only the speed of an object but also the direction in which it is moving. Speed, on the other hand, only measures how fast an object is moving without considering its direction. For instance, when tracking a severe storm that’s headed your way, it’s essential to understand both its speed and direction in order to predict its path and potential impact.

Acceleration is the rate of change of velocity.  Acceleration occurs when an object changes speed, direction, or both.  To calculate the acceleration of an object, the change in velocity is divided by the length of the time interval over which the change occurred.

Accelerating quickly puts a lot of force on an object.  Depending on the speed and direction, acceleration can be positive or negative. Positive acceleration is evident when a plane speeds up to take off, while negative acceleration occurs when a bike slows down.

Review:

1. Define velocity.
2. When does acceleration occur?
3. Compare positive acceleration to negative acceleration.