Two bodies of masses 8 kg and 5 kg travelling in the same direction with speeds x m/s and 2 m/s respectively collide. If after collision, they move together with a speed of 3.85 m/s, find, correct to the nearest whole number, the value of x.
-
A.
2 -
B.
5 -
C.
8 -
D.
13
Correct Answer: Option B
Explanation
((m_{1} v_{1} + m_{2} v_{2}) = (m_{1} + m_{2})v) (Inelastic momentum)
(8x + (5 times 2) = (8 + 5) times 3.85)
(8x + 10 = 13 times 3.85 = 50.05)
(8x = 50.05 – 10 = 40.05)
(x approxeq 5 m/s)