Correct Answer - Option 4 : 29.53 kg
Concept:
mrω2 = Bbω2
mr = Bb
m = mass to be balanced, B = Mass required for balancing the mass.
r and b are the radius of mass to be balanced and mass required for balancing.
Calculation:
Given:
mass of reciprocating parts = 40 kg, mass of revolving parts = 30 kg at crank radius, speed = 150 rpm, stroke = 350 mm
60% of the reciprocating parts and all the revolving parts are to be balanced
b = 320 mm, Stroke = 2r = 350 mm, ∴ r = 175 mm.
Mass to be balanced
m = mrot + 0.60mreci
m = 30 + (0.60)*40 = 54 kg
mr = Bb
54 × 175 = B × 320
B = 29.53 kg