A body of mass 10kg moving with a velocity of 5(ms^{-1}) collides with another body of mass 15kg moving in the same direction as the first with a velocity of 2(ms^{-1}). After collision, the two bodies move together with a common velocity v(ms^{-1}).
-
A.
3.2 -
B.
5.3 -
C.
7.0 -
D.
8.0
Correct Answer: Option A
Explanation
Momentum of bodies with common velocity = (m_{1}v_{1} + m_{2}v_{2} = (m_{1} + m_{2})v)
((10 times 5) + (15 times 2) = (10 + 15)v)
(50 + 30 = 25v implies v = frac{80}{25} = 3.2ms^{-1})