In physics, what is the difference between acceleration and deceleration?

Question

• In physics, is acceleration suppose to be positive or negative? 
• In physics, is deceleration suppose to be positive or negative?
• What is the difference between acceleration and deceleration?

Answer 1

Answers

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1. What is the difference between acceleration and deceleration in physics?

• Acceleration is the rate of change of velocity with respect to time. It can increase or decrease the speed of an object, or change its direction.

• Deceleration is a type of acceleration where the velocity of an object decreases — meaning the object is slowing down.

In short:

• Acceleration can be positive or negative depending on direction.

• Deceleration refers specifically to acceleration that reduces speed.

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2. In physics, is acceleration supposed to be positive or negative?

• Acceleration can be either positive or negative, depending on the chosen direction (frame of reference).

  • Positive acceleration means velocity is increasing in the positive direction.

  • Negative acceleration means either:

    • Velocity is increasing in the negative direction, or

    • Velocity is decreasing in the positive direction.

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3. In physics, is deceleration supposed to be positive or negative?

• Deceleration is usually considered a negative acceleration when an object is slowing down in the positive direction.

However, whether it's “positive” or “negative” depends on how you define your direction:

• If a car is moving forward and slowing down, the acceleration is negative.

• If a car is moving backward and slowing down, the acceleration could be positive (since it's reducing speed in the negative direction).

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Summary of Differences:

Concept	Acceleration	Deceleration
Definition	Change in velocity over time	Negative acceleration (slowing down)
Direction	Can be positive or negative	Always opposes the motion
Effect on Speed	Can increase or decrease speed	Always decreases speed