décélération

Décélération is a term used in physics to describe a decrease in speed or velocity. It is the opposite of acceleration, which is an increase in speed or velocity. When an object decelerates, its velocity is changing in the direction opposite to its motion. This change in velocity is also a form of acceleration, specifically negative acceleration.

In everyday language, deceleration is often referred to as slowing down. For example, when a car applies its brakes, it decelerates. A ball thrown upwards decelerates as it rises due to gravity, eventually reaching a point of zero velocity before it begins to accelerate downwards.

Mathematically, deceleration can be calculated using the same formulas as acceleration, but with a negative value for acceleration. If an object has an initial velocity v_i and a final velocity v_f over a time interval Δt, its acceleration a is given by a = (v_f - v_i) / Δt. If v_f is less than v_i, and both are in the same direction, the value of 'a' will be negative, indicating deceleration.

The concept of deceleration is fundamental in understanding motion and its changes. It is crucial in fields like kinematics, mechanics, and engineering, particularly in areas involving the control of movement, such as vehicle braking systems or the trajectory of projectiles. Understanding deceleration helps predict how objects will change their speed and motion over time.