Inelastic Collisions in Two Dimensions: a Car Heading North Collides

Multiple Choice

Inelastic collisions in two dimensions: A car heading north collides at an intersection with a truck of the same mass as the car heading east. If they lock together and travel at 28 m/s at 46° north of east just after the collision, how fast was the car initially traveling? Assume that any other unbalanced forces are negligible.

A) 40 m/s
B) 20 m/s
C) 80 m/s
D) 30 m/s