Relationship between Velocity and Acceleration

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Discussion Overview

The discussion revolves around the relationship between velocity and acceleration, particularly in the context of a car decelerating when brakes are applied. Participants explore the concepts of vector quantities, the direction of acceleration, and how these relate to changes in velocity.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether the statement that "the direction of acceleration will be the same as the direction of velocity" is true or false, expressing confusion about the direction of acceleration during deceleration.
  • Another participant explains that acceleration indicates the direction in which velocity is increasing, using the example of a lift to illustrate the concepts of acceleration and deceleration.
  • Some participants assert that when a car decelerates, it must accelerate in the opposite direction to its velocity, suggesting that the car accelerates backwards when brakes are applied.
  • There is a clarification that both velocity and acceleration are vector quantities, and that acceleration represents the rate of change of the velocity vector.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between velocity and acceleration, particularly regarding the direction of acceleration during deceleration. Some assert that acceleration must be in the opposite direction to velocity when deceleration occurs, while others provide explanations that may not align with this view.

Contextual Notes

Participants reference vector addition and the nature of vector quantities, but there are unresolved aspects regarding the definitions and implications of acceleration and deceleration in different contexts.

Muhammad Danish
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When the driver applies brakes its velocity starts decreasing and direction of acceleration will be same to the direction of velocity.
Is this statement True of False?
Please explain the true concept of this scenario. As far as I understand is that Velocity will start decreasing. But I am confused regarding the ''Direction of Acceleration''.
Thanks.
(REGARDS)
 
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Acceleration means which direction or axis is the car increasing in velocity.

Imagine a lift moving up and down. It is currently moving up with constant velocity. The lift now needs to stop so it begins to DECELERATE in the direction upwards and ACCELERATE downwards. Acceleration means an increasing velocity in one direction and deceleration means a decreasing velocity in the other direction. This applies even if the lift isn't moving in the direction of acceleration or deceleration.

Can you apply this to your car?
 
lekh2003 said:
Acceleration means which direction or axis is the car increasing in velocity.

Imagine a lift moving up and down. It is currently moving up with constant velocity. The lift now needs to stop so it begins to DECELERATE in the direction upwards and ACCELERATE downwards. Acceleration means an increasing velocity in one direction and deceleration means a decreasing velocity in the other direction. This applies even if the lift isn't moving in the direction of acceleration or deceleration.

Can you apply this to your car?
Oh so will it mean that the car must accelerate backwards??
 
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Muhammad Danish said:
When the driver applies brakes its velocity starts decreasing and direction of acceleration will be same to the direction of velocity.
Is this statement True of False?
Please explain the true concept of this scenario. As far as I understand is that Velocity will start decreasing. But I am confused regarding the ''Direction of Acceleration''.
Thanks.
(REGARDS)
The statement is false. Velocity and acceleration are vector quantities, and acceleration represents the rate of change of the velocity vector. Do you know what a vector is? If so, do you know how to perform vector addition and subtraction?
 
Chestermiller said:
The statement is false. Velocity and acceleration are vector quantities, and acceleration represents the rate of change of the velocity vector. Do you know what a vector is? If so, do you know how to perform vector addition and subtraction?
Yes, addition of vectors can be done by taking a scale and drawing a parallelogram or a triangle. By using triangle/parallelogram law of vector addition, we can find the resultant. Vector is a quantity that is described by both direction and magnitude.
 
Muhammad Danish said:
Oh so will it mean that the car must accelerate backwards??
Yes
 
Muhammad Danish said:
Oh so will it mean that the car must accelerate backwards??
Yes, this is what happens. The direction of the velocity mustn't be in the direction of acceleration for it to be accelerating/decelerating.
 
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