Question

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

Answer 1

application of center of masa

Answer 2

The distance of the centre of mass from the origin is 40cm

Mass 1 = m1 = 300g (Given)

Mass 2 = m2 = 500g (Given)

Mass 3 = m3 = 400g (Given)

Centre of mass when more mass is added in the body -  

rCM = m1r1 + m2r2 / m1+m2

where m1 and r1 are the mass and position of center of mass for whole body and m2 and r2 are the mass and position of center of mass of the added mass.

Xc = m1x1 + m2x2 + m3x3 / m1 + m2 + m3

Xc = 300 × 0 + 500 × 40 + 400 × 70/ 300 + 500 + 400

Xc = 120/3

Xc = 40

The distance of the centre of mass from the origin is 40cm