Question

16-g mass is moving in the +x direction at 30 cm/s while a 4-g mass is moving in the -x direction at 50 cm/s. they collide head on and stick together. find their velocity after the collision.

Answer 1

16*30 - 4*50 = 20 v

Answer 2

From the - x direction, m1v1 =4*(-50) =-200gm/s
And from +x direction, m2v2=16 *30=480
Where M1V1 + M2V2=(M1 + M2)V.
=> - 200 + 480 =(4+16)v
V= 280/20 =14m/s.