The head of a rattlesnake can accelerate at 49 m/s2 in striking a victim. If a car could do as well, how long would it take to reach a speed of 81 km/h from rest?

Time taken is 0.459 seconds

Explanation:

We have equation of motion v = u + at

Initial velocity, u = 0 m/s

Final velocity, v = 81 km/hr = 22.5 m/s

Time, t = ?

Acceleration, a = 49 m/s²

Substituting

v = u + at

22.5 = 0 + 49 x t

t = 0.459 seconds

Time taken is 0.459 seconds