BITSAT2024PhysicsCenter of Mass, Momentum and CollisionActual
Two bodies of mass 1 kg and 3 kg have position vectors i +2 j +k and -3 i -2 j + k respectively. The magnitude of position vector of centre of mass of this system will be similar to the magnitude of vector :
Options
- Ai -2 j + k
- B-3 i -2 j + k
- C-2 i +2 k
- D-2 i - j +2 k
Correct answer
A. i -2 j + k
Step-by-step solution
Position of COM of a mass - system is given as, r _ com = m₁ r ₁+m₂ r ₂ m₁+m₂ = 1( i +2 j + k )+3(-3 i -2 j + k 1+3 =-2 i - j + k | r _ c m |=|-2 i - j + k |= (2)^2+(1)^2+(1)^2 = 6 Only option (1) magnitude is 1^2+(-2)^2+1^2 = 6 So option (1) is correct.