20. Two spacemen A and B are floating is gravityfree space with zero v

1.	20. Two spacemen A and B are floating is gravityfree space with zero velocity relative to eachother. "A" has a mass of 120 kg and "B" has amass of 90kg which includes a 5 kg radio box."B" throws the box towards "A" with a velocityof 2m/x and A catches it. The change invelocity of each one is1) VA = 11.8cm/s v B=8cm/s2) VA = 8cm/s v =11.8cm/s3) VA = 10cm/s 0 B=10cm/s4) va = 9cm/s 0 B=12cm/s
Answer» ANSWER: Option (2) $V_A=8\text{ cm/s}, V_B=11.8\text{ cm/s}$ EXPLANATION: Mass of A = 120 kg Mass of B = 85 kg Mass of radio box = 5 kg B throws the box towards A with velocity 2 m/s Initial velocity of B = 0 Let final velocity of B is $V_B$ Therefore, from conservation of linear momentum $0=2\times5-V_B\times85$ $\implies V_B=\frac{10}{85} = 0.1176 \text{ m/s}$ = 11.8 cm/s Again from conservation of linear momentum, if the velocity of A after receiving the radio box is $V_A$ then $2\times5=V_A\times(120+5)$ $\implies V_A=\frac{10}{125} = 0.08 \text{ m/s}$ = 8 cm/s