Question

Un turist are in spate un rucsac cu masa de 20kg.Determina masa turistului daca,aflindu-se in repaus el exercita asupra podelei o presiune de 15kPascali.Aria talpilor incaltamintelor este de 600cm2

Answer 1

$m_2=20 \ kg \\ g=10 \ N/kg \\ p=15 \ kPa=15 \ 000 \ Pa \\ S=600 \ cm^2=0,06 \ m^2 \\ \boxed{m_1-?} \\ \bold{Rezolvare:} \\ \boxed{p= \frac{F_n}{S}} \\ F_n=G_1+G_2 \\ \Rightarrow G_1=F_n-G_2 \\ F_n=p \cdot S \\ F_n=15 \ 000 \ Pa \cdot 0,06 \ m^2 \\ F_n=900 \ N \\ G_2=m_2 \cdot g \\ G_2=20 \ kg \cdot 10 \ N/kg \\ G_2=200 \ N \\ G_1=900 \ N=200 \ N \\ G_1=700 \ N \\ m_1= \frac{G_1}{g} \\ m_1= \frac{700 \ N}{10 \ N/kg} \\ \Rightarrow \boxed{m_1=70 \ kg}$