Question

A 270 g bird flying along at 5.0 m/s sees a 11 g insect heading straight toward it with a speed of 35 m/s (as measured by an observer on the ground, not by the bird). The bird opens its mouth wide and enjoys a nice lunch.
What is the bird's speed immediately after swallowing?

Answer 1

Answer:

The bird's speed immediately after swallowing is 6.17 m/s.

Explanation:

Given that,

Mass of the bird, m = 270 g = 0.27 kg

Initial speed of the bird, u = 5 m/s

Mass of the insect, m' = 11 g = 0.011 kg

Initial speed of the insect, u' = 35 m/s

We need to find the bird's speed immediately after swallowing. Let it is given by V. Using the conservation of momentum as :

$mu+m'u'=(m+m')V\\\\V=\dfrac{mu+m'u'}{(m+m')}\\\\V=\dfrac{0.27\times 5+0.011\times 35}{(0.27+0.011)}\\\\V=6.17\ m/s$

So, the bird's speed immediately after swallowing is 6.17 m/s.