Chapter 5, Problem 17RQ

When a cannonball is fired, is momentum conserved for the cannon-cannonball system as a whole? (Why is your answer different than in the previous two questions?)

To determine

Whether the momentum conserved for the cannon-cannonball system as a whole and the reason for the different answer than the previous two questions.

Answer to Problem 17RQ

The momentum of the cannon-cannonball system remains conserve because no external force is acting for the whole system.

Explanation of Solution

When the cannonball is fired, the explosion occurs due to the internal force of the cannonball. The internal force of the cannonball provides the equal and opposite force for the cannon. This equal and opposite force acts as the external force for the cannon.

If the cannon-cannonball acts as a system then there is no external force acting on the whole system. The momentum of the cannon-cannonball remains conserve because no external force is acting on the whole system.

The answers of the previous two questions are different because in those questions cannon and cannonball are considered as the separate systems. If the analysis for the cannon and cannonball is done as a single system, then the momentum for the cannonball remains conserved.

Conclusion:

Therefore, the momentum of the cannon-cannonball system remains conserved because no external force is acting for the whole system.