A 20-Kg Ball Moving Eastward at 3 $6.0 \mathrm{~kg}=\mathrm{m} / \mathrm{s}$

Multiple Choice

A 2.0-kg ball moving eastward at 3.0 m/s suddenly collides with and sticks to a 4.0-kg ball moving northward at 2.0 m/s. What is the magnitude of the momentum of this system just after the collision?

A) $6.0 \mathrm{~kg}=\mathrm{m} / \mathrm{s}$
B) $8.0 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$
C) $10 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$
D) $14 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$
E) $2.0 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$