|Since there two masses involved
at the same time, we name the mass on the table m1 and the hanging mass m2
. This way we can distinguish them in the equations.
Ff = Fg = m2g
At the same time.
Ff = FN
m2g = m1g
However, there is one condition we have to consider, Ff
must equal Fg (m2g). This means that the system
must be moving at constant speed, since there's no net force, and in turn no acceleration.
Loooking at the forces that acts on the system, we ignored
air resistance. Fg , m1g cancels out with FN and
rope tension cancels each other out since they're going in different directions.