The Difference Between Speed & Velocity

Summary

In this video, the speaker explains the difference between speed and velocity. While both terms might seem similar, speed is a scalar quantity, representing only distance over time, whereas velocity is a vector, which includes direction. For example, if you're cycling at 5 kilometers per hour, that's your speed. However, if you cycle in a circle and return to your starting point, your velocity is zero since there's no directional change. The video clarifies these concepts with simple examples, helping viewers understand the fundamental difference between speed and velocity.

Takeaways

• 😀 The speaker is answering a question from a young physics student about the difference between speed and velocity.
• 🤔 The speaker once thought speed and velocity were the same but now clarifies the difference.
• 📏 Speed is a scalar quantity, meaning it only has magnitude (distance over time).
• 🧭 Velocity is a vector, which means it has both magnitude and direction.
• 🚴‍♂️ Speed example: If you ride your bicycle at 5 kilometers per hour to the park, your speed is 5 kilometers per hour.
• 🧭 Velocity example: If you move in a circle and return to the same point, your speed remains, but your velocity is zero because there is no directional gain.
• 🚶‍♀️ In the example of walking different distances in various directions, if you return to your starting point, your average velocity is zero.
• ↔️ Speed is like distance (how far you've traveled), while velocity is like displacement (how far you are from the starting point).
• 💡 The speaker offers to make a video explaining the difference between distance and displacement if viewers are unsure.
• 🎥 The speaker mentions working on longer videos while this one is a quick explanation.

Q & A

What is the key difference between speed and velocity?

The key difference is that velocity includes a direction, while speed does not. Speed is a scalar quantity, while velocity is a vector.

Why is speed called a scalar quantity?

Speed is called a scalar quantity because it only has magnitude (the rate at which an object covers distance) and does not include any information about direction.

Why is velocity referred to as a vector quantity?

Velocity is referred to as a vector quantity because it includes both magnitude (the rate of motion) and direction.

Can you provide an example of speed and velocity using the same numerical value?

Yes. If someone is traveling at 30 kilometers per hour, that is a measure of speed. If they are traveling at 30 kilometers per hour toward the north, that becomes velocity since it includes direction.

How does the example of a cyclist going to the park illustrate speed?

In the example, the cyclist travels at a constant speed of 5 kilometers per hour to the park. The speed is simply the distance covered divided by the time taken, which is 5 kilometers per hour.

What happens to the velocity of the cyclist if they return to the same starting point?

If the cyclist returns to the same starting point, their velocity becomes zero because the displacement (change in position) is zero, even though they traveled a certain distance.

Why is velocity zero even if the cyclist was moving at a speed of 5 kilometers per hour?

Velocity depends on the displacement. If the cyclist returns to the starting point, their displacement is zero, making the velocity zero, despite having a non-zero speed.

How is displacement related to velocity?

Displacement is a vector quantity that refers to the change in position from the starting point. Velocity is dependent on displacement, not the total distance traveled.

What would be the average velocity if someone walked in a square and returned to the starting point?

The average velocity would be zero because the person ends up at the starting point, meaning there is no change in position or displacement.

How is distance different from displacement?

Distance is the total length of the path traveled, while displacement is the shortest straight line between the starting and ending points, including direction.