F ds

dA = F*ds*cos(alpha)

,

dA = (F1+F2+F3+...+Fn)*ds = dA1+dA2+dA3+...+dAn

: . - [A] = .

- . - . [N] = .

:

N = dA/dt.

N = (F*ds)/dt = Fv.

 

 

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