Question

a system consisting of a two masses are connected by a massless rod lies along the x-axis. if 0.2 kg mass is at the distance x is equal to 0.5 m while a 0.3 kg mass is at a distance x is equal to 1m then the x coordinates of the centre of mass will be at
A) 2.5m B) 5m C) 22.5 D) 0.8

Answer 1

m1 = 0.4 , m2 = 0.6 
x1 = 2 , x2 = 7
X = (m1x1 + m2x2)/(m1+m2)
  = (0.8 + 4.2)/(0.4+0.6)
X = 5 m.

Answer 2

A system consisting of a two masses are connected by a massless rod lies along the x-axis. if 0.2 kg mass is at the distance x is equal to 0.5 m while a 0.3 kg mass is at a distance x is equal to 1m then the x coordinates of the centre of mass will be at

A) 2.5m B) 5m C) 22.5 D) 0.8

Answer:

Here m1 = 0.4 , and m2 = 0.6

x1 = 2 , and x2 = 7

Let X be the coordinate of the central of mass. Then

X = (m1x1 + m2x2)/(m1+m2)

= (0.8 + 4.2)/(0.4+0.6)

X = 5 m.

Answer. B)5m