• Support PF! Buy your school textbooks, materials and every day products via PF Here!

Distance < Displacement

  • Thread starter jacyh
  • Start date
4
0
Why is the distance never less than the displacement?
I can't seem to find a scientific explanation for it. :confused:
 
8
0
think about travelling half way around a circle, the distance travelled would be half the circumference, and the displacement would be the diameter.

in this case distance > displacement

distance can be equal to the displacement (if you travel in a straight line), but it can never be less.
 
4
0
distance can be equal to the displacement (if you travel in a straight line), but it can never be less.

I know, but... why? Haha.
 
8
0
just think about the example i gave you and think of any other ones you can think of..... the displacement will never be greater than the distance.

Think of distance as "distance travelled"

So if you're going from point A to point B in any situation you can think of (around curves, over mountains etc...) The distance travelled will be greater because you had travel "around" things.
The displacement is a straight line between point A and B, so it is always the shortest possible distance.
 
Last edited:

robphy

Science Advisor
Homework Helper
Insights Author
Gold Member
5,381
661
Strictly speaking, distance is a magnitude but displacement is a vector.
So, yoiu really mean
"why is distance >= magnitude of displacement ?"

Mathematically,
[tex] \int \left| d\vec s \right| \geq \left| \int d\vec s \right| [/tex]

Essentially, distance [ the arc-length of a curve from A to B ] is the sum of non-negative quantities.
The magntude of displacement [ the magnitude of a vector from A to B ] is the non-negative magnitude of a sum-of-(signed)-vector-quantities.
The proof of the inequality is essentially the triangle inequality.
 
102
0
distance is total distance traveled, displacement is from the initial location to the final location.
 
113
1
The displacement is the shortest way possible from the start to the finish (that is, it's a line); thus, nothing can be shorter.
 

Related Threads for: Distance < Displacement

  • Posted
Replies
16
Views
2K
  • Posted
Replies
2
Views
4K
  • Posted
Replies
23
Views
1K
Replies
27
Views
1K
  • Posted
Replies
5
Views
2K
  • Posted
Replies
3
Views
831
Replies
2
Views
1K
  • Posted
Replies
19
Views
1K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top