Why total time taken s₁/v₁ + s₂/v₂ + s₃/v₃ in average speed?

[jbriggs444]

Vavg = d1 + d2 / t1 + t2?

What are d₁ and d₂? We have two points, A and B with distance d between them.

[Note that parentheses matter]

 

[Indranil]

What are d₁ and d₂? We have two points, A and B with distance d between them.

[Note that parentheses matter]

Vavg = s / t ?

 

[jbriggs444]

Vavg = s / t ?

What's s? We have two points A and B with distance d between them.

 

[Indranil]

What's s? We have two points A and B with distance d between them.

could you mention the equation, please?

 

[jbriggs444]

could you mention the equation, please?

No. That's your job.

 

[Indranil]

No. That's your job.

Vavg = 2d / t?

 

[Indranil]

Vavg = 2d / t?

Could anyone clarify me please Vavg = 2d / t? I am waiting for the replies.

 

[Stephen Tashi]

t1 + t2 = d / v1 + d / v2, t = d (v1 + v2) / v1v2,

Yes

Vavg = d / t

No, in the problem you are considering the total distance is d + d = 2d because you travel distance d from point A to point B and then travel distance d again when you go from point B back to point A.

but the equeation is 2v1v2 / v1 + v2

You are complicating the discussion by writing fractions incorrectly. You omit paretheses that are needed.
You write "2v1v2/ v1 + v2" when you actually mean "2v1v2/ (v1 + v2)"

 

[Indranil]

YesNo, in the problem you are considering the total distance is d + d = 2d because you travel distance d from point A to point B and then travel distance d again when you go from point B back to point A.You are complicating the discussion by writing fractions incorrectly. You omit paretheses that are needed.
You write "2v1v2/ v1 + v2" when you actually mean "2v1v2/ (v1 + v2)"

I got it now. I will check myself. please find my faults so that I can improve myself in Physics. I am learning a lot from this site. one more equation
If t₁ = t₂ = t₃ =...tn, Vav = (v₁ + v₂ +...+ vn)t / nt
What's the concept behind the equation above? Could you clarify it, please?

 

[Stephen Tashi]

one more equation
If t₁ = t₂ = t₃ =...tn, Vav = (v₁ + v₂ +...+ vn)t / nt
What's the concept behind the equation above?

The proper format of a physics problem is to have a statement of the problem in words. In that statement, the variables are defined. After the variables are defined in words, equations are written.

You give an equation, but you omit the description of the problem in words and you omit defining the variables.

Many of the homework advisors are capable of seeing an equation and guessing what words describe the problem. However, if you rely on other people to "read your mind", you won't learn to write clearly.

Explain the situation and define the variables that are used.

 

[Indranil]

The proper format of a physics problem is to have a statement of the problem in words. In that statement, the variables are defined. After the variables are defined in words, equations are written.

You give an equation, but you omit the description of the problem in words and you omit defining the variables.

Many of the homework advisors are capable of seeing an equation and guessing what words describe the problem. However, if you rely on other people to "read your mind", you won't learn to write clearly.

Explain the situation and define the variables that are used.

Thank you for your kind advice. I'll try to follow.
If t₁ = t₂ = t₃ =...= tn, Then we have Vavg = (v₁ + v₂ +...+Vn)t / nt
What is the concept behind this formula?

 

[Indranil]

What does 'tn' and 'Vn' mean in the equation below?
'If t₁ = t₂ = t₃ =...= tn, Then we have Vavg = (v₁ + v₂ +...+Vn)t / nt' Could you explain please?

 

[Nugatory]

You have $n$ time intervals, all equally long. $t_1$ is the length of the first interval, $t_2$ is the length of the second one, and so forth.

 

[Indranil]

You have $n$ time intervals, all equally long. $t_1$ is the length of the first interval, $t_2$ is the length of the second one, and so forth.

I don't understand clearly. Could you explain it in detail, please?

 

[Indranil]

Thank you for your kind advice. I'll try to follow.
If t₁ = t₂ = t₃ =...= tn, Then we have Vavg = (v₁ + v₂ +...+Vn)t / nt
What is the concept behind this formula?

If t₁ = t₂ = t₃ =...= tn, Then we have Vavg = (v₁ + v₂ +...+Vn)t / nt
What is the concept behind this formula?
I am waiting for the replies

 

[Stephen Tashi]

If t₁ = t₂ = t₃ =...= tn, Then we have Vavg = (v₁ + v₂ +...+Vn)t / nt
What is the concept behind this formula?
I am waiting for the replies

You have not yet made a complete description of the problem in words. If the problem is written in English, please quote the entire problem. Don't merely quote fragments from it.

If you are translating the problem from another language into English, try to translate each sentence.

 

[Doc Al]

If t₁ = t₂ = t₃ =...= tn, Then we have Vavg = (v₁ + v₂ +...+Vn)t / nt
What is the concept behind this formula?

The concept behind this formula is the same as all the others: V_ave = Distance/Time. Of all the formulas you've been asking about, this basic definition of average speed is the one you need to have down cold. All the rest can be derived from this with a little algebra.

You seem to be obsessing over several formulas that are only useful in very specific situations. (The formula quoted in this post is an example of that -- it's only true under very specific assumptions.) Unless you specify the problem you are trying to solve -- and thus define what the variables mean in your equations -- we can only guess at what you're trying to do. (Admittedly, we are pretty good guessers. But we shouldn't have to guess.)