A bullet is fired from a gun. The force on the bullet is given by `F=600-2xx10^(5)` t, where F is in newtons and t in seconds. The force on the bullet becomes zero as soon as it leaves the barrel. What is the average impulse imparted to the bullet?

Options

A. `9 N - s`
B. zero
C. `0.9 N - s`
D. `1.8 N - s`

Answer

C

Explanation

`F = 600 - 2 xx 10^(5) t = 0 xx t rArr 3 xx 10^(-3) s`
Impulse `= int_(0)^(t) F dt = int_(0)^(t) (600 - 2 xx 10^(5) t) dt`
`= 600 t - 10^(5) t^(2)`
`= 600 xx 3 xx 10^(-3) - 10^(5) ( 3 xx 10^(-3))^(2)`
`= 1.8 - 0.9 = 0.9 N -s`