What's the "d" in that formula? (work formula)

[Austin Gibson]

What's the definition of the "d" in that formula?

 

[.Scott]

It a basic calculus term: "differential" or "delta". It indicates a change.
In this case, most likely a change as a function of time.

https://en.wikipedia.org/wiki/Differential_calculus

 

[Austin Gibson]

It a basic calculus term: "differential" or "delta". It indicates a change.
In this case, most likely a change as a function of time.

https://en.wikipedia.org/wiki/Differential_calculus

This equation assumes a constant force?

 

[ZapperZ]

This equation assumes a constant force?

No it doesn't. This is because to find W, you have to integrate F over the appropriate range of dr.

Zz.

 

[robphy]

dW=\vec F \cdot d\vec r is an infinitesimal amount work done over the infinitesimal displacement d\vec r,
where \vec F is approximately constant during that displacement.

When this is evaluated over a path, then \vec F and d\vec r will vary as you progress along the path.

It's probably not a good idea to think of these d's as differentials (as in dW is a differential of W
since there is generally no such W because the work done generally depends on the path. In thermodynamics books, this is sometimes written as đW.)