The Difference Between Speed & Velocity
Summary
TLDRIn 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.
Outlines
📧 Introduction and Question from a Student
The speaker introduces the video by mentioning that they are working on various interesting projects. They are responding to an email from a young physics student, who asks a question about the difference between speed and velocity. The speaker expresses that this is an excellent and insightful question, even admitting that they once thought the two terms were the same.
⚡ Defining Speed vs. Velocity
The speaker explains that speed and velocity are not the same. Speed is a scalar quantity, meaning it only describes magnitude (distance over time), while velocity is a vector, which includes both magnitude and direction. For example, '30 kilometers per hour' is a measure of speed, but '30 kilometers per hour north' describes velocity because it includes direction.
🚴 Simple Example: Riding a Bicycle
To illustrate the difference, the speaker gives an example of riding a bicycle at 5 kilometers per hour. The speed is simply the distance covered over time. However, if the rider moves in a circle and returns to the starting point, the velocity is zero because there has been no change in the directional displacement, despite the speed being 5 kilometers per hour.
🔄 Clarifying Velocity with Directional Change
The speaker further explains that even if you move in different directions (e.g., 4 meters forward, 2 meters sideways, etc.), the average velocity could still be zero if you return to the starting point. This is because velocity depends on the net change in direction or displacement, not just the distance traveled.
💬 Conclusion and Call for Engagement
In closing, the speaker highlights that the difference between speed and velocity is similar to the distinction between distance and displacement. They invite viewers to comment if they need further clarification, offering to make additional videos on related topics. The speaker wraps up with a quick note, mentioning that longer videos are in the works.
Mindmap
Keywords
💡Speed
💡Velocity
💡Scalar
💡Vector
💡Distance
💡Displacement
💡Direction
💡Circular Motion
💡Average Velocity
💡Kilometers per hour
Highlights
Introduction to the topic and responding to a young physics student's email about the difference between speed and velocity.
Clarifies that speed and velocity are often confused, even the speaker once thought they were the same.
Explains that the key difference between speed and velocity is that velocity has direction, while speed does not.
Defines speed as a scalar quantity and velocity as a vector quantity in physics.
Provides an example of speed: '30 kilometers per hour' as it indicates distance over time, making it a scalar quantity.
Defines velocity as speed with a directional component, such as '30 kilometers per hour to the north.'
Introduces a simple bicycle example to explain the concept of speed: cycling at 5 kilometers per hour to a park.
Elaborates on velocity using the example of moving in a circle and returning to the starting point — speed remains, but velocity becomes zero due to no net displacement.
Further emphasizes that speed is the measure of distance over time, while velocity depends on directional displacement.
Compares the difference between speed and velocity to the difference between distance and displacement.
Offers to explain the concept of distance vs displacement further if there are requests in the comments.
Concludes the video by thanking the audience and mentioning upcoming videos.
The speaker adds that this was a short video ('quickie') while working on longer content.
The speaker invites audience engagement and feedback by asking viewers to comment below with questions.
Background music plays as the video comes to a close.
Transcripts
hello everybody today I'm answering an
email that I got from a young physics
student while I'm working on an array of
really cool videos that I'm sure you
guys are gonna like so the question is
what is the difference between speed and
velocity that is an interesting and
excellent question
because I - at some point thought they
were the same thing now as per usual I'm
going to tell you what the difference is
in words and then I will explain it with
an easy example so basically the
difference between them is that velocity
has a direction while speed does not in
physics we call speed a scalar quantity
while velocity is a vector that means
that if we take this expression 30
kilometers per hour just like that now
this is speed because it says distance
over time so this is by definition speed
as simple as that but for velocity now
this expression would look something
like 30 kilometers per hour in the north
direction or dear north now let's take a
look at a very simple example if you
took your bicycle and you want to go to
the park if you're riding your bicycle
at five kilometers per hour until you
reach the park then your speed is five
kilometers per hour is the distance that
you have covered in the time it took you
to cover it before velocity like I said
it has to do with the direction so for
example if you start from point A and
you go with that speed in a circle and
then you come back to point a again the
exact same point then we say your speed
here is five kilometre per hour but your
velocity here is zero and the reason it
is zero is because there is no
directional game you started it in the
same point and then you came back at the
same point again even if you were to
walk four meters this way two meters
this way four meters this way and then
two meters up here then your velocity or
average velocity is zero can
per hour the difference between the two
it's like the difference between
distance and displacement basically if
you're not sure about that one
comment below and I will make a very
quick video like this about it thank you
so much guys just a quickie today while
I'm working on different videos that are
longer now we'll see on the next one
[Music]
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