Three steel spheres move along the same straight line

PHYSICS · Subjective · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics

Problem

Three steel spheres move along the same straight line. Sphere 1 has mass

0.50\,\text{kg}

and velocity

4.0\,\text{m\,s}^{-1}

east. Sphere 2 has mass

1.0\,\text{kg}

and is initially at rest. Sphere 3 has mass

2.0\,\text{kg}

and velocity

1.0\,\text{m\,s}^{-1}

west. Determine the velocity (magnitude and direction) of the center of mass of the three-sphere system at this instant.