# How long does it take for the bullet velocity in the barrel of a Kalashnikov assault rifle to increase

**How long does it take for the bullet velocity in the barrel of a Kalashnikov assault rifle to increase from 0 to 715 m / s? Bullet acceleration 600000 m / s2.**

If the body moves rectilinearly and uniformly accelerated, then its speed v depends on the time of movement t according to the law v = v₀ + a ∙ t, where v₀ is the speed at the moment of observation, and is the acceleration with which the body moves. Then:

t = (v – v₀) / a.

It is known from the problem statement that the bullet in the barrel of a Kalashnikov assault rifle moves with acceleration a = 600,000 m / s ^ 2, increasing the velocity from v₀ = 0 m / s to v = 715 m / s. We substitute the values of the quantities into the calculation formula and find how long it takes for such an increase in speed to occur:

t = (715 m / s – 0 m / s) / 600,000 m / s ^ 2;

t = 0.0012 s = 1.2 ms.

Answer: in 1.2 ms.