Answer:686 kg-m/s
Explanation:
Given
mass of tony [tex]m_1=70 kg[/tex]
mass of bicycle [tex]m_2=20 kg[/tex]
mass of pack [tex]m_3=8 kg[/tex]
Speed of tony [tex]v=7 m/s[/tex]
Tony throw a pack at 4 m/s relative to the speed of bicycle
[tex]Momentum= mass\times velocity[/tex]
Bike, tony and Pack have the same velocity v=7 m/s before the throw
Momentum just before throw is
[tex]P_{initial}=(m_1+m_2+m+3)\cdot v[/tex]
[tex]P_{initial}=(70+20+8)\cdot 7=686 Kg-m/s[/tex]
