Question

Ajuta-ti-ma va rog!!

Answer 1

pai le aduni cred
eh nustiu dar cted ca e bn succes la teme

Answer 2

Se da:
[tex]m=100dag=1kg\\ h=5m\\ l=5m\\ F_{fr}= \frac{1}{10}G=\ \textgreater \ u=0,1\\ g=10N/kg\\ a)Ec_{B}=?J\\ b)Ec_{C}=?J\\ c)h'=?m\\ [/tex]

Rezolvare:
Planurile sint lipsite de frecare, astfel putem folosi legea conservarii energiei mecanice.

[tex]a)Ep_{max_{A}}=Ec_{max_{B}}\\ Ec_{B}=mgh\\[/tex]

b)Pe portiunea BC, ne va fi comod sa folosim transformarea energiei mecanice in lucru. 

[tex]deltaEc=L_{N}+L_{G}+L_{F_{fr}}\\ Ec_{C}-Ec_{B}=L_{F_{fr}}\\ Ec_{C}=Ec_{B}+L_{F_{fr}}\\ Ec_{C}=Ec_{B}-F_{fr}*l\\ Ec_{C}=Ec_{B}-u*N*l\\ Ec_{C}=Ec_{B}-u*G*l\\ Ec_{C}=Ec_{B}-u*m*g*l\\[/tex]

[tex]c)Ec_{max_{C}=Ep_{max_{D}}\\ Ec_{C}=m*g*h'\\ h'= \frac{Ec_{C}}{m*g} \\[/tex]

Calcule:
[tex]a)Ec_{B}=1*10*5=50J\\ b)Ec_{C}=50-0,1*1*10*5=45J\\ c)h'= \frac{45}{1*10}=4,5m \\[/tex]