Two bodies of masses 3kg and 5kg moving with velocities 2 m/s and V m/s respectively in opposite directions collide. If they move together after collision with velocity 3.5 m/s in the direction of the 5kg mass, find the value of V.
A. 7.8 m/s B. 6.8 m/s C. 5.6 m/s D. 4.6 m/s
Correct Answer: B
Explanation
Since the bodies are in an opposite direction, one takes the negative velocity. \(m_{1}v_{1} + m_{2}v_{2} = (m_{1} + m_{2})v\) (Momentum when the two bodies move in the same direction after collision) \(3(-2) + 5(V) = (3 + 5)3.5\) \(-6 + 5V = 28 \implies 5V = 34; V = 6.8 m/s\)
