I'd go with electricity source. Good luck!!
Answer:
10miles/second
Explanation:
Change in velocity of the bird is expressed as the difference between the final velocity and initial velocity of the body.
Change in velocity = Final velocity - initial velocity
Since the bird takes off from the tree, the initial velocity of the bird = 0miles/sec
Final velocity = 10miles/secs
Change in velocity = 10-0
Change in velocity = 10miles/second
The other 4 kg of mass may have departed the scene
of the fire, in the form of gases and smoke particles.