Negative velocity signifies movement in the opposite direction of the defined positive direction. It's crucial to understand that velocity is a vector quantity, meaning it has both magnitude (speed) and direction.
Here's a breakdown:
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Velocity as a Vector: Velocity describes how quickly an object is changing its position and in what direction.
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Defining Positive Direction: When analyzing motion, you first establish a positive direction (e.g., to the right, upwards, North).
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Interpreting Negative Velocity:
- If an object is moving in the direction opposite to the chosen positive direction, its velocity is negative.
- The negative sign doesn't mean the object is slowing down; it only indicates direction.
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Example: Imagine a car moving along a straight road.
- If we define movement to the East as positive, a car traveling East at 30 m/s has a velocity of +30 m/s.
- A car traveling West at 30 m/s has a velocity of -30 m/s. Its speed is still 30 m/s, but the negative sign indicates its direction is westward.
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Speed vs. Velocity: Speed is the magnitude (absolute value) of velocity. Therefore, speed is always a positive value or zero. The velocity includes the directional component.
| Quantity | Definition | Can be Negative? |
|---|---|---|
| Velocity | Rate of change of position with direction | Yes |
| Speed | Magnitude of velocity | No |
In essence, negative velocity just informs you about the direction of motion relative to your chosen frame of reference.
