Two masses of 6 and 2 unit, are at positions (6i^-7j^) and (2i^ + 5j^-8k^) respectively. The coordinates of the centre of mass are [JIPMER 2017]

Given, masses, m1 = 6 unit and m2 = 2 unitPositions = 6i^-7j^ and 2i^ + 5j^-8k^Coordinates of centre of mass are calculated below          xCM=m1x1+m2x2m1+m2=6×6+2×26+2=36+48=5i^         yCM=m1y1+m2y2m1+m2=6×(-7)+2×(5)6+2                 =-42+108=-4j^and     zCM=m1z1+m2z2m1+m2=6×(0)+2×(-8)6+2=-168=-2k^∴ Centre of mass lies at 5i^-4j^-2k^.⇒ Coordinates of centre of mass are (5, -4, -2).