Answer:
The final speed of the railroad car
V= 1.14 [tex]\frac{m}{s}[/tex]
Explanation:
[tex]v_{1}=2.1\frac{m}{s} \\m_{1}=12000kg\\v_{2}=0\frac{m}{s} \\m_{2}=10000kg \\v_{t}=?[/tex]
[tex]m_{1}*v_{1}+m_{2}*v_{2}= (m_{1}+m_{2})*v_{t}\\v_{t}=\frac{m_{1}*v_{1}}{(m_{1}+m_{2})} \\v_{t}=\frac{12000kg*2.1\frac{m}{s} }{(12000+10000)kg} \\v_{t}=1.14 \frac{m}{s}[/tex]
That's the final speed of the both railroad car