average impulse

Question

a bullet is fired from a gun. The force on the bullet is given by F=600-2*10⁵ t, where F  is in Newton and t is in second. The force on the bullet become zero as soon as it leaves the  barrel.  What is the average impulse imparted ot the bullet

Answer 1

To answer this question, we need to know how long the force acted on the bullet, which was not provided in the problem statement.  Suppose the force acted on the bullet for a time interval of duration T, which would be from when the explosive charge in the bullet was set off, until the bullet has cleared the gun barrel.

 

I = impulse in kg·m/s

 

I = ∫₀^T F(t)dt = ∫₀^T [600 - (2 x 10⁵)t]dt

 

Do the integration, plug in the correct value of T, and get your answer in kg·m/s.