1. Change in Velocity (Δv): This refers to how much the velocity of an object changes. A larger change in velocity means a greater acceleration.

2. Time Interval (Δt): This refers to the amount of time it takes for the change in velocity to occur. A shorter time interval means a greater acceleration.

The relationship between acceleration, change in velocity, and time interval is expressed by the following equation:

Acceleration (a) = Change in Velocity (Δv) / Time Interval (Δt)

This means:

* Direct Proportionality: Acceleration is directly proportional to the change in velocity. If the change in velocity increases, the acceleration increases, and vice versa, assuming the time interval remains constant.

* Inverse Proportionality: Acceleration is inversely proportional to the time interval. If the time interval increases, the acceleration decreases, and vice versa, assuming the change in velocity remains constant.

Example:

* A car accelerating from 0 to 60 mph in 5 seconds has a greater acceleration than a car accelerating from 0 to 60 mph in 10 seconds. This is because the change in velocity is the same, but the time interval is shorter in the first case.

* A car accelerating from 0 to 30 mph has a smaller acceleration than a car accelerating from 0 to 60 mph in the same amount of time. This is because the change in velocity is smaller in the first case.