Câu 8:
$P=\dfrac{A}{t}=\dfrac{P.h}{t}=\dfrac{60.6}{0,5.60}=12W$
Câu 9:
Ta có: $A_{tp}=H.A_{i}$
$⇔P.h=80\%.F_{c}.h_{lún}$
$⇔10.100.5=80\%.F_{c}.0,4$
$⇔F_{c}=16625N$
Câu 10:
$P_{A}=\dfrac{A}{t}=\dfrac{P.h}{t}=\dfrac{10.1100.6}{60}=1100W$
$P_{B}=\dfrac{A'}{t'}=\dfrac{P'.h'}{t'}=\dfrac{10.800.5}{30}=1333.(3)W$
$⇒P_{B}>P_{A}$