Question

Two particles of masses 2 g and 36 g respectively are attached to two ends of a
rigid light rod of length 1.9 m. The centre of the mass of the system from 2 g
particle is nearly at distance of
1.4 m
1.8 m
1.7 m
0.95 m​

Answer 1

Given:

Two particles of masses 2 g and 36 g respectively are attached to two ends of a rigid light rod of length 1.9 m.

To find:

Centre of mass ?

Calculation:

• Let's assume that the rod is placed along the the X axis. So, 2 gram particle is at point (0,0) and 36 gram particle is at (1.9,0).

$\overline{x} = \dfrac{ \sum( m_{i} x_{i}) }{ \sum( m_{i}) }$

$\implies \overline{x} = \dfrac{ (2 \times 0) + (36\times 1.9) }{(2 + 36) }$

$\implies \overline{x} = \dfrac{ 36\times 1.9}{38 }$

$\implies \overline{x} = 1.8 \: m$

• Y coordinate of C-O-M will be 0.

So, the coordinate of Centre of Mass is (1.8, 0).

• Centre of mass will be at a distance of 1.8 metres of 2 gram particle.

• OPTION 2) IS CORRECT