When a rattlesnake strikes, its head acceler-

ates from rest to a speed of 21 m/s in 0.46 s
seconds. Assume for simplicity that the only
moving part of the snake is its head of mass
200 g.
How much (average) power does the rat-
tlesnake need to accelerate its head that fast?
Answer in units of W.

m = 0.2 kg

Ke = (1/2) m v^2 = work done = power*time
so
power = [(1/2) m v^2] / .46 Watts