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31 votes
31 votes
A large 2.71 kg bird, searching for food, spots a large, 0.384 kg bug hovering in its vicinity. If the bird is traveling at 8.8 m/s, what will be his velocity immediately after nabbing the bug?

User Hymloth
by
3.1k points

1 Answer

22 votes
22 votes

The initial momentum of the system can be given as,


p_i=m_1u_1+m_2u_2

The final momentum of the system can be expressed as,


p_f=(m_1+m_2)v

According to conservation of momentum,


p_i=p_f

Plug in the known expressions,


\begin{gathered} m_1u_1+m_2u_2=(m_1+m_2)v \\ v=(m_1u_1+m_2u_2)/(m_1+m_2) \end{gathered}

Substitute the known values,


\begin{gathered} v=\frac{(2.71\text{ kg)(8.8 m/s)+(0.384 kg)(0 m/s)}}{2.71\text{ kg+0.384 kg}} \\ =\frac{23.848\text{ kgm/s}}{3.094\text{ kg}} \\ \approx7.71\text{ m/s} \end{gathered}

Thus, the velocity after nabbing the bug is 7.71 m/s.

User Oskenso Kashi
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3.2k points