A bullet is fired from a gun, the force on the bullet is given by F=600−2×105t where F is in newton and t in second. The force on the bullet becomes zero as soon as it leaves the barrel. What is the average impulse imparted to a bullet?

 Force acting on the bullet is given as

⇒ F=600−2×105t

⇒ t=600/2×105 

t = 3×10−3s

Now impulse imparted by the bullet is I=

So, we get ⇒I=|600t−2×105t2/2|3×10−3

 ∴ I = 0.9Ns