Question: 24. Two bodies A and B of same mass undergo completely inelastic one dimensional collision. The body A moves with velocity v_{1} while body B is at rest before collision. The velocity of the system after collision is v_{2}. The ratio v_{1}: v_{2} is :
(1) 1: 2
(2) 2: 1
(3) 4: 1
(4) 1: 4
Answer: Option (2)
Explanation:
Let the mass of each body be m.
Before collision, body A moves with velocity v_{1} and body B is at rest.
Initial momentum of the system is
p_{\text{initial}} = mv_{1} + m \times 0 = mv_{1}In a completely inelastic collision, the two bodies stick together after collision.
Total mass after collision becomes 2m
and the common velocity is v_{2}.
Final momentum of the system is
p_{\text{final}} = 2m v_{2}Using conservation of linear momentum,
mv_{1} = 2m v_{2}Dividing both sides by m,
v_{1} = 2v_{2}Therefore, the ratio is
v_{1} : v_{2} = 2 : 1Hence, the correct answer is Option (2).