# Negative acceleration, deceleration and decreasing acceleration

What is the difference between decreasing acceleration, deceleration and negative acceleration? Most importantly, i want to clarify that acceleration is the rate of change of velocity over time, it Does not necessarily mean that the car velocity is increasing and that a car is speeding up when it is said to be accelerating right?

Decreasing acceleration can occur in both the positive ad negative direction, for example braking is a form of decreasing acceleration in the positive direction, right? In this case I am Not referring to a positive change in acceleration, but a decrease in velocity which is decreasing at a decreasing rate in the positive direction. DA can also be applied in the negative direction., in this case moving backwards is considered as negative, where the car reverses back at a velocity whic is decreasing at a decreasing rate , or increasing at a decreasing rate.
Negative acceleration is acceleration in the negative direction, right? It doesn't necessarily mean a negative change in acceleration right ? It can mean that a car is moving in the negative direction but it's velocity is increasing in the negative direction, right?
Which brings me on to the next question, what is deceleration? Deceleration is when the car's speed is decreasing, and the car can be moving both forward or backwards , right? Please feel free to correct me if you think I am wrong and state your opinions to help me be able to visualise better for different situations and circumstances! Thank you!

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What is the difference between decreasing acceleration, deceleration and negative acceleration? Most importantly, i want to clarify that acceleration is the rate of change of velocity over time, it Does not necessarily mean that the car velocity is increasing and that a car is speeding up when it is said to be accelerating right?
While the term acceleration has a precise definition, I don't think the other terms do. Acceleration can involve speeding up, slowing down, or changing direction.

Deceleration is often used to mean slowing down. Negative acceleration can simply mean an acceleration in the negative direction. Decreasing acceleration might mean changing the acceleration in the negative direction or simply that the magnitude of the acceleration is decreasing. You'd have to consider the context in which each of those terms might be used.

Yup ok but so far my concepts of the terms are correct right !

Braking might not represent decreasing acceleration, it would represent decreasing velocity, but the magnitude of acceleration might increase, decrease or stay the same.

Ah yes. I agree with you. 