A single cylinder reciprocating engine has a reciprocating mass of 50 kg. The crank rotates at 80 rpm and the stroke is 300 mm. Mass of revolving parts at 150 mm radius is 40 kg. If 2/3rd of the reciprocating parts and whole of the revolving parts are to be balanced, determine

(a) the balance mass required at a radius of 340 mm, and

(b) the unbalanced force when the crank has turned through 40° form TDC.