Write an expression for the net force on block A consistent with the positive direction as given in the problem statement.
a) ( Fₙet, A = mA ⋅ aₙet )
b) ( Fₙet, A = mA ⋅ g )
c) ( Fₙet, A = mA ⋅ dvA/dt )
d) ( Fₙet, A = mA ⋅ agravity )