Is This the Best Formula for Calculating Work and Time?

  • Context: High School 
  • Thread starter Thread starter momentum
  • Start date Start date
  • Tags Tags
    Formula Time Work
Click For Summary

Discussion Overview

The discussion revolves around the formulas for calculating work and time in the context of mathematical problems involving multiple workers. Participants explore different approaches to express these relationships and clarify the terminology used.

Discussion Character

  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant proposes a formula: N1 * D1 * W1 = N2 * D2 * W2, where N represents the number of persons, D the number of days, and W the work done.
  • Another participant introduces the physics formula for work, W = F s, questioning the relevance of physics in the context of the mathematical problems being discussed.
  • A participant clarifies that they are focusing on mathematical problems, specifically those involving man-hours, and seeks to confirm the formula they initially posted.
  • One participant suggests an alternative formula: N_1 R D_1 = W = N_2 R D_2, where R is the rate of work done per man, and provides an example to illustrate this concept.
  • Another participant questions the meaning of the rate of work per man and requests an example.
  • A participant emphasizes that the problem can be simplified to a common-sense approach, likening it to the formula for distance, and provides a detailed example of calculating total work based on the number of workers and their rate of work.
  • One participant expresses a humorous opinion about the nature of such word problems, suggesting that they are unrealistic.
  • A later reply agrees with the initial formula but presents it with a slight modification in terms of the variables used.
  • Another participant critiques the term "work" as being vague and prefers a more specific term like "rate of work per day per man."
  • One participant expresses agreement with the explanation of work but maintains that their formula is superior.

Areas of Agreement / Disagreement

Participants express differing views on the correct formula to use for calculating work and time, with no consensus reached on a single formula. Some participants support the initial formula, while others propose alternatives and emphasize the importance of defining terms clearly.

Contextual Notes

Participants highlight the need for clarity in definitions, particularly regarding the term "work," and the assumptions made about the rate of work per person. There are unresolved questions about the applicability of different formulas in various contexts.

momentum
Messages
111
Reaction score
0
Hi,

whats the formula for work and Time ?


is it this ?

N1 * D1 * W1 =N2*D2*W2

where ,
N1=No of Persons
D1=No of days
W1=work


N2=No of Persons
D2=No of days
W2=work


is that's formula correct for work and time ?
 
Mathematics news on Phys.org
The simplest formula for mechanical work (in Physics) is
W = F s
Here, the force is contant and parallel to displacement and the body moves in a steady direction. W is work, F is force and s is displacement. The result is in Joules.

Unless you want manhours? What exactly are you trying to do? :)
 
no...there is no physics involved in it.

i'm talking about maths.

problems like..."20 man works for 10 days did a work, how long it would be taken by 30 man"?

this kind of problem

whats the formula ?

I have forgotten the formula...is it like same as i posted ?
 
N_1 R D_1 = W = N_2 R D_2

Where: N = number of men; R = rate of work done per man (assumed constant); D = days (or time); W = total work done.
 
>R = rate of work done per man (assumed constant);

what does it mean ?

can you give an example of it ?

thank you
 
Don't treat this as some esoteric formula from the ancients. It should be just "common sense", a variation of "Distance = Rate X time".

An example of R would be: a man can lift 50 bales of hay per day, so R = 50 bales/day/man.

So, if one man can lift 50 per day, how much total can be lifted in 3 days by 5 men?

Using W = N R D gives, W(total) = (5 men) (50 bales/day/man) (3 days) = 750 bales

But to solve a problem like " if 20 men working 10 days did a certain amount of work, how long would it take 30 men to do the same work?" you don't have to know R. Just use:

N_1 R D_1 = W = N_2 R D_2
(20)(R)(10) = (30)(R)(D_2)

Note that the Rs just drop out, and D_2 = 20/3 days.
 
Those are the dumbest of word problems. I would be tempted to answer : "The job would never get done, because the extra men would entice the entire lot to unionise and strike for better pay and conditions".
 
this is correct
N1 * D1 * W2 =N2*D2*W1
where ,
N1=No of Persons
D1=No of days
W1=work


N2=No of Persons
D2=No of days
W2=work
 
Except that just "work" is meaningless. I prefer Doc Al's "rate of work per day per man".
 
  • #10
yes bro u r right for "work" explanation but except tht mine formula is best one
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 18 ·
Replies
18
Views
2K
  • · Replies 22 ·
Replies
22
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K