Three masses are placed on the x-axis : 300 g at origin,

Three masses are placed on the x-axis : 300 g at origin, 500 g at x = 40 cm and 400 g at x = 70 cm. The distance of the centre of mass from the origin is :

X_cm =	m₁x₁ + m₂x₂ + m₃x₃
	m₁ + m₂ + m₃

X_cm =	300 × (0) + 500 × (40) + 400 × (70)
	300 + 500 + 400

X_cm =	500 × 40 + 400 × 70
	1200

X_cm =	50 + 70	=	120	= 40 cm
	3		3