Question

va rog frumos ajutor la 3​

Answer 1

Răspuns:

C) 40 secunde

Explicație:

formula puterii mecanice $\boxed{P = \frac{L}{\Delta t}}$

$\displaystyle{ \Delta t = \frac{L}{P} = \frac{mgh}{P} }$

$\displaystyle{ \Delta t = \frac{4000 \cdot 10 \cdot 20}{20 \cdot 1000} }$

$\displaystyle{ \Delta t = \frac{800.000}{20.000} = 40 \ s }$