Given a 10 kg toy truck moved at 5 m/s east.
[tex]\begin{gathered} p_1=(10kg)\times(5\text{ m/s)} \\ p_1=\frac{50kg.m}{s} \end{gathered}[/tex]It collided head-on with a 5kg toy car moving 10m/s moving west.
[tex]\begin{gathered} p_2=(5kg)\times(-10\text{ m/s)} \\ p_2=-\frac{50kg.m}{s} \end{gathered}[/tex]Setting the eastward direction as positive and the westward direction as negative, you can easily calculate the total momentum of the system.
Adding the +50 kg.m/s with -50 kg.m/s gives a sum of zero.
[tex]\frac{50kg.m}{s}-\frac{50kg.m}{s}=0[/tex]Thus, the total momentum of the system is zero.
