A 30-Kg Mass Sliding on a Frictionless Surface Explodes into Three

Multiple Choice

A 3.0-kg mass sliding on a frictionless surface explodes into three 1.0-kg masses. After the explosion the velocities of the three masses are: (1) 9.0 m/s, north; (2) 4.0 m/s, 30° south of west; and (3) 4.0 m/s, 30° south of east. What was the magnitude of the original velocity of the 3.0-kg mass?

A) 1.7 m/s
B) 1.0 m/s
C) 1.3 m/s
D) 2.0 m/s
E) 2.8 m/s