Answer:
[tex]v=-5.97\,\frac{m}{s}[/tex]
Explanation:
The system boy-skateboard can be modelled by means of the Principle of Momentum Conservation:
[tex](48.2\,kg)\cdot (10.2\,\frac{m}{s} ) = (46.2\,kg)\cdot (10.9\,\frac{m}{s} )+(2\,kg)\cdot v[/tex]
The final velocity of the skateboard:
[tex]v=-5.97\,\frac{m}{s}[/tex]