Question

Socorroooooooooooooooo

Answer 1

Tc=m(C).a
Tb-Tc=m(B).a
P(A)-Ta=m(A).a ...somando as equacoes
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P(A)=(m(A)+m(B)+m(C)).a
2.10=(2+4+4).a
a=20/10
a=2 m/s²

Tc=m(C).a
Tc=4.2
Tc=8 N

Tb-Tc=m(B).a
Tb-8=4.2
Tb=8+8
Tb=16 N

boa sorte :)