Q.

Two objects of mass 10 kg and 20 kg respectively are connected to the two ends of a rigid rod of length 10 m with negligible mass. The distance of the center of mass of the system from the 10 kg mass is               [2022]
 

1 103m  
2 203m  
3 10 m  
4 5 m  

Ans.

(2)

Masses, m1=10kg and m2=20kg

Let the distance between the two masses be d=10m.

Now, centre of masses for two particle system is written as,

XCOM=m1x1+m2x2m1+m2                                                      ...(i)

Considering point A as origin, so B=(d,0)

XCOM=(m1×0+m2dm1+m2)=m2dm1+m2

XCOM=20kg×10m10kg+20kg=203m