Answer:v=0.4 m/s
Explanation:
Mass hockey player [tex]m_1=90 kg[/tex]
mass of cup [tex]m_2=10 kg[/tex]
Velocity of cup [tex]u=4 m/s[/tex]
let v be the velocity of the combined system
Conserving momentum
[tex]m_1\cdot 0+m_2u=(m_1+m_2)v[/tex]
[tex]v=\frac{10\times 4}{100}[/tex]
[tex]v=\frac{40}{100}[/tex]
[tex]v=0.4 m/s[/tex]