Question

Demonstrati ca P=F*v (puterea=forta*viteza), stiind ca puterea=lucru mecanic pe timp.

Answer 1

P=L/t=F*d/t=F*v Deci P=F*v v=d/t

Answer 2

$P=F \cdot v, \ deoarece: \\ P= \frac{L}{t} , \ iar \ de \ unde \ L=F \cdot d, \ iar \ t= \frac{d}{v}, \ caci \ v= \frac{d}{t}; \\ Inlocuim \ si \ obtinem: \ P= \frac{L}{t} = \frac{F \cdot d}{ \frac{d}{v} } = \frac{F \cdot d}{1} : \frac{d}{v} = \frac{F \cdot d}{1} \cdot \frac{v}{d} ; \\ Simplificam \ distanta \ din \ ambele \ parti \ si \ obtinem: \\ P= \frac{F}{1} \cdot \frac{v}{1} =\boxed{F \cdot v}$