In physical science, acceleration is defined as the rate of change of velocity over time. It's a vector quantity, meaning it has both magnitude (how much) and direction.

Here's a breakdown:

* Magnitude: This refers to how quickly the velocity is changing. A higher magnitude of acceleration means the velocity is changing rapidly.

* Direction: This indicates the direction of the change in velocity. Acceleration can be in the same direction as the velocity (speeding up), in the opposite direction (slowing down), or perpendicular to the velocity (changing direction).

Key points about acceleration:

* Units: Acceleration is typically measured in meters per second squared (m/s²).

* Constant Acceleration: Objects moving with constant acceleration undergo a steady change in velocity.

* Zero Acceleration: An object at rest or moving at a constant velocity has zero acceleration.

* Gravity: Earth's gravity provides a constant acceleration of approximately 9.8 m/s² downwards.

Formulas:

* Acceleration (a) = Change in velocity (Δv) / Change in time (Δt)

* a = (v_f - v_i) / (t_f - t_i)

Where:

* v_f is the final velocity

* v_i is the initial velocity

* t_f is the final time

* t_i is the initial time

Examples:

* A car speeding up from 0 to 60 mph in 5 seconds is accelerating.

* A ball thrown upwards slows down as it goes up, indicating negative acceleration.

* A car turning a corner at a constant speed is still accelerating because its direction is changing.

Understanding acceleration is crucial in many areas of physics, including mechanics, kinematics, and dynamics. It helps us explain and predict the motion of objects.