A300 g bird flying along at 5.5 m/s sees a 10g insect heading straight toward it with a speed of 25 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?
/s

Bird's speed immediately after swallowing = 4.52 m/s

Explanation:

Here momentum is conserved.

Initial momentum = Final momentum

Mass of bird = 300 g = 0.3 kg

Velocity of bird = 5.5 m/s

Mass of insect = 10 g = 0.01 kg

Velocity of insect = -25 m/s ( opposite to the motion of bird)

Initial momentum = 0.3 x 5.5 + 0.01 x -25 = 1.4 kgm/s

Final mass = 0.3 + 0.01 = 0.31 kg

Initial momentum = Final momentum = 1.4 kgm/s

                 1.4 = 0.31 x Bird's speed immediately after swallowing

         Bird's speed immediately after swallowing = 4.52 m/s

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up