- Thread starter shahar
- Start date

- Joined
- Jun 18, 2007

- Messages
- 24,649

Do a Google search!!What is the difference between these two?

Tell us what you find - and what are you confused regarding the responses you found.

- Joined
- Jun 18, 2007

- Messages
- 24,649

OK,O.K. I will ask it differently:

When they are equal?

and when they are have not the some values?

In a system of the two same bodies?

The answer is

Do a Google search and tell us what you found!

Tell us exactly where you are confused!

- Joined
- Nov 12, 2017

- Messages
- 11,526

Why would two bodies be involved, in a question about one average speed or velocity? If there is more background for your question, tell us! How many dimensions do you have in mind?O.K. I will ask it differently:

When they are equal?

and when they are have not the some values?

In a system of the two same bodies?

Do you know the difference between speed and velocity, ignoring "average"?

Don't just rephrase your question, answer ours!

- Joined
- Jan 27, 2012

- Messages
- 7,535

If my velocity is "50 mph southeast" my speed is "50 mph".

If I go 10 miles east at 30 mph and then 10 miles west at 30 mph I wind up right back where I started as if I hadn't moved at all. My average speed was 30 mph but my average velocity was 0 mph,

- Joined
- Nov 12, 2017

- Messages
- 11,526

- Joined
- Jun 18, 2007

- Messages
- 24,649

Inaverage velocity \(\displaystyle = \frac{\int_{t_0}^{t_f} v(t) \, dt}{t_f - t_0}\)

average speed \(\displaystyle = \frac{\int_{t_0}^{t_f} |v(t)| \, dt}{t_f - t_0}\)

average constant

average constant

Instantaneous speed is the magnitude of the instantaneous velocity.

Average constant speed is **NOT **the magnitude of the average constant velocity.

The integration mentioned above (for v(t)) would be

- Joined
- Dec 15, 2005

- Messages
- 2,948

mechanics, the definition is:

average constantspeedof a particle = (distance travelled by the particle in time δt)/(δt) ........................................ distance is a scalar quantity

average constantvelocityof a particle = (displacementthe particle in time δt)/(δt) ........................................displacementis a vector quantity

Instantaneous speed is the magnitude of the instantaneous velocity.Average constant speed isNOTthe magnitude of the average constant velocity.

The integration mentioned above (for v(t)) would beline integrationor contour integration (of the vector) along the path. Complication arises in a curved path - more non-intuitively in a self-intersecting path.