Is velocity technically a force? Is it drawn as vector in free-body-diagrams?

In summary: A diagram needs to serve a purpose.And it shouldn't be ambiguous.So you should either draw "only" forces, or "only" velocities.And still, you can mix them, if it helps explaining how something works.But make sure then that they are easy to distinguish, for instance by using different colors.In summary, a velocity is not a force, but can be drawn in free body diagrams.
  • #1
Femme_physics
Gold Member
2,550
1
Is "velocity" technically a force? Is it drawn as vector in free-body-diagrams?

The reaosn I'm asking that is because I was told by a physics expert that you only draw forces in free body diagrams. I also see the velocity (as well as angular velocity) indicated in a lot of free-body-diagrams in my dynamics exercises solution manual.

http://img190.imageshack.us/img190/6449/veloc.jpg [Broken]Now I'm confused :confused:
 
Last edited by a moderator:
Physics news on Phys.org
  • #2


Perhaps, these pictures are simply no free-body diagrams but depicting the kinematics of the motion under consideration. In free-body diagrams, you should have indeed only forces!
 
  • #3


Awww, it's not as strict as all that. :smile:

A diagram needs to serve a purpose.
And it shouldn't be ambiguous.

So you should either draw "only" forces, or "only" velocities.
And still, you can mix them, if it helps explaining how something works.
But make sure then that they are easy to distinguish, for instance by using different colors.
(You like colors, don't you? :biggrin: I like smileys! :cool:)

FBD's are specifically used to analyze the forces acting on the body, which tends to be difficult to do right!
So if you want to make a proper analysis, be careful what else you put in!

The diagrams you have, show "only" velocities, making them unambiguous!
I'm not sure you would call them "free body diagrams" (http://en.wikipedia.org/wiki/Free_body_diagram" [Broken]), but you certainly wouldn't call them "force diagrams".
I guess you might call them "velocity diagrams"! :smile:

But really, dictionary English is not my strong suit! :wink:
 
Last edited by a moderator:
  • #4


You can draw whatever you like in a diagram. Just don't add force vectors to velocity vectors, or apples to oranges, or...
 
  • #5


Force diagram - Velocity diagrams

My brain welcomes your logic! Thanks, ILS :)

And thanks vanhees for feedbacking^^
 
  • #6


Obviously a "velocity" is not a "force"...just look at the units for each...

But as noted, you can draw what you like to help explain a situation. In static diagrams there is often no ambiguity about direction and motion, say due to gravity; but in dynamic situations it can be helpful to include velocity/momentum direction...also more here:

http://en.wikipedia.org/wiki/Free_body_diagram
 

1. Is velocity a force?

No, velocity is not considered a force. Velocity is a measure of an object's speed and direction, while force is a measure of the push or pull on an object. They are two separate quantities in physics.

2. Can velocity be represented as a vector in free-body-diagrams?

Yes, velocity can be represented as a vector in free-body-diagrams. A vector is a quantity that has both magnitude and direction, and velocity is a vector quantity. It is typically represented by an arrow, with the length of the arrow indicating the magnitude of the velocity and the direction of the arrow indicating the direction of the velocity.

3. What is the difference between velocity and speed?

Velocity and speed are often used interchangeably in everyday language, but in physics, they have different meanings. Velocity is a vector quantity that includes both the speed and direction of an object, while speed is a scalar quantity that only describes how fast an object is moving without considering direction.

4. How is velocity related to acceleration?

Velocity and acceleration are related in that acceleration is the rate of change of velocity over time. In other words, acceleration measures how much an object's velocity changes in a certain amount of time. This relationship is described by the equation a = Δv/Δt, where a is acceleration, Δv is the change in velocity, and Δt is the change in time.

5. Can an object have a constant velocity and still have a non-zero net force?

Yes, it is possible for an object to have a constant velocity and still have a non-zero net force acting on it. This is known as uniform circular motion, where an object moves in a circular path at a constant speed, but the direction of its velocity is constantly changing. In this case, the net force is directed towards the center of the circle, providing the necessary centripetal force to keep the object moving in a circular path.

Similar threads

Replies
8
Views
948
Replies
3
Views
3K
Replies
14
Views
2K
Replies
6
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
381
  • Mechanics
Replies
5
Views
6K
  • Introductory Physics Homework Help
Replies
4
Views
988
Back
Top