Physics
Physics
Problem
A rifle of mass fires a bullet of mass horizontally to the right. The bullet leaves the rifle with a speed of relative to the ground. The bullet experiences a uniform acceleration while inside the barrel for . Neglect any external forces other than the interaction between the bullet and the rifle. a. (i) Calculate the average force exerted by the rifle on the bullet while the bullet is in the barrel. b. (ii) Write the force exerted by the bullet on the rifle, including its direction. c. (iii) Using your answer to part (ii), determine the recoil acceleration of the rifle while the bullet is being fired. State its direction clearly.Intuitive explanation
This is a momentum conservation problem where you need to recognize that the rifle and bullet form an isolated system—so total momentum before firing equals total momentum after. Since both start at rest, the rifle must recoil backward with just enough momentum to balance the bullet's forward momentum. Once you find the rifle's recoil speed, you can use kinematics to find the bullet's acceleration inside the barrel.
Intuitive explanation
This is a momentum conservation problem where you need to recognize that the rifle and bullet form an isolated system—so total momentum before firing equals total momentum after. Since both start at rest, the rifle must recoil backward with just enough momentum to balance the bullet's forward momentum. Once you find the rifle's recoil speed, you can use kinematics to find the bullet's acceleration inside the barrel.