Question

ajutor! Rezolvati-mi problema
Dau coroana + multe puncte​

Answer 1

ΔEc_AB=L_G+L_N

ΔEc=Ec_B-Ec_A=mv₂²/2-mv₁²/2

L_G=mgh ; L_N=0

mv₂²/2-mv₁²/2=mgh  |:m/2=>v₂²-v₁²=2gh<=>v₂²=2*10*2+3²=40+9=49=>v₂=√49=7 m/s

ΔEc_BC=L_G+L_N+L_Ff

L_G=0  ; L_N=0  ; L_Ff=-μmgd

Ec_C=0

ΔEc_BC=Ec_C-Ec_B=-mv₂²/2

-mv₂²/2=-μmgd |:(-m)/2=>v₂²=2μgd<=>7²=0,8*10*d<=>49=8d=>d=49/8=6,12 m