Mg − FT = Ma (2)We add the equations (thereby eliminating FT) and solve for a. Notice that, by
definition, Ff =μFN and from the free-body diagram for m, we see that FN = mg, so
Ff = μmg:
Or, using our shorter method:
Substituting in the numerical values given for m, M, and μk, we find that a = g (or
7.5 m/s^2 ).
The Mass Effect
Both masses are accelerating
at the same right, as
the system of masses is