Speed vs Velocity: What's the Difference?

In summary, velocity is a vector quantity that takes into account both magnitude and direction, while speed is simply the magnitude of velocity. This means that even if the speed remains constant, a change in direction will result in a change in velocity. This highlights the importance of considering both speed and direction when traveling to a specific destination. Additionally, it is important to understand that a change in direction is considered an acceleration, even if the speed remains constant.
  • #1
jaysun_83
8
0
What is the difference between speed and velocity?
 
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  • #2
The usual meanings are that velocity is a vector, having magnitude and direction, while speed is just the magnitude of velocity.
 
  • #3
Suppose you are heading east with a speed of 1 m/s. If you change your direction towards north but keep your speed=1 m/s, then though your speed has not changed, your velocity changes. This is because velocity depends both on the speed with which one is going, and the direction in which he/she is going.
So how does velocity make a difference when used instead of speed? Suppose that you have to go straight north with a speed x m/s to reach a shop. Now you get out of your home and start walking southwards. What is your speed? x m/s. But with this speed, are you ever going to reach your market? No (unless you are brave enough to walk the whole length of earth, to reach that point). Why? If you are traveling with the required speed, what is the problem in reaching the market? The problem is that your direction is wrong or, in other words, your velocity is just opposite to what you should actually have.
So, are you now able to grasp the difference between speed and velocity?

regards
Mr V
 
  • #4
Mr Virtual said:
Suppose you are heading east with a speed of 1 m/s. If you change your direction towards north but keep your speed=1 m/s, then though your speed has not changed, your velocity changes.

Just to add something that might clear up misconceptions that appear to be common: that change of direction is an acceleration, even though the speed remains constant.
 
  • #5
Yeah, thanks Mr. Virtual. And thanks for the addition Danger, understanding that change of direction is an acceleration explains a lot to me also.
 
  • #6
No worries, mate. The whole point is that 'acceleration' is defined as a change of velocity. If either the magnitude or the vector changes, then the term applies.
 

1. What is the difference between speed and velocity?

Speed and velocity are both measures of how fast an object is moving. However, speed only tells us the magnitude of the object's movement, while velocity also includes the direction of the movement. In other words, velocity is a vector quantity while speed is a scalar quantity.

2. How are speed and velocity calculated?

Speed can be calculated by dividing the distance traveled by the time it took to travel that distance. Velocity, on the other hand, is calculated by dividing the displacement (change in position) by the time it took to make that displacement.

3. Can an object have a constant speed but changing velocity?

Yes, an object can have a constant speed but changing velocity. This occurs when the object is moving in a circular path at a constant speed. Since its direction is constantly changing, its velocity is also constantly changing even though its speed remains constant.

4. Which is more important in determining an object's motion, speed or velocity?

Both speed and velocity are important in determining an object's motion. Speed tells us how fast an object is moving, while velocity also tells us the direction of the movement. In some cases, the direction of an object's movement can be more important than its speed, for example when considering the path of a projectile.

5. How do speed and velocity relate to acceleration?

Acceleration is the rate of change of an object's velocity over time. So, if an object's velocity is changing, it is accelerating. This means that an object can have a constant speed but still be accelerating if its direction is changing. However, if an object's speed is constant and its direction is not changing, then its acceleration is equal to 0.

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