4.5.7.2 Conservation of Momentum

Question 1

Conservation of momentum:

Answer 1

• in a closed system, the total momentum before an event is equal to the total momentum after an event
• applies to collisions and explosions

Question 2

Cannon ball example for conservation of momentum:

Answer 2

• cannon containing a cannon ball
• before the cannon fires, both the cannon and the cannonball are not moving
• total momentum before firing = 0
• when the cannon fires the cannon ball is moving at a very large velocity so the cannonball has momentum in the forward direction
• at the same time the cannon recoils this means the cannon has momentum acting in the backwards direction
• the backwards momentum of the cannon = the forwards momentum of the cannonball
• this means the total momentum after firing is equal to 0
• so the momentum has been conserved