Răspuns :
Vectorial:F+N+G+Ff=ma
Scalar:Ox:F-mgsinα-Ff=ma
Oy:N-mgcosα=0=>N=mgcosα
Ff=μN=μmgcosα
F-mgsinα-μmgcosα=ma=>a=(F-mgsinα-μmgcosα)/m=(21-2*10*1/2-1*2*10*√3/2√3)/2=(21-10-10)/2=1/2=0,5 m/s²
x=vot+at²/2=0+0,5*6²/2=0,5*36/2=9 m
v=vo+at=0+0,5*6=3 m/s
Vectorial:N+Ff+G=m*au
Scalar:Ox:-mgsinα-Ff=m*au
Oy:N-mgcosα=0=>N=mgcosα
Ff=μN=μmgcosα
-mgsinα-μmgcosα=m*au |:m=>au=-g(sinα+μcosα)=-10(0,5+0,5)=-10 m/s²
dop=vm*top
vm=v/2=>dop=v*top/2
au=Δv/Δt=-v/top=>top=-v/au=>dop=-v²/2au=-3²/2(-10)=9/20=0,45 m