4. The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ? = Angular speed of crank, r = Radius of crank, and ? = Angle of inclination of crank to the line of stroke)
9. A disturbing mass m1 attached to the rotating shaft may be balanced by a single mass m2 attached in the same plane of rotation as that of m1, such that (where r1 and r2 are the radii of rotation of m1 and m2 respectively)