Question

In travelling the 70cm along a rifle barrel, a bullet uniformly accelerates from rest to a velocity of 210m/s .Find the acceleration involved and the time taken for which the bullet is in the barrel.​

Answer 1

S = 1/2 a t^2 since intial speed is zero

Vav = 210 m/s / 2 = 105 m/s

t = .7 m / 105 m/s = 6.67E-3 sec (6.67 * 10^-3 s)

a = 2 S / t^2

a = 2 * .7 / (6.67E-3)^2

a = 31,500 m/s^2

Check:

Ave Speed * time = length of barrel

105 * 6.67E-3 = .70 m