Explosions (Also seen in GCSE Physics 2)

We look at explosions in the same way as we look at collisions, the total momentum before is equal to the total momentum after. In explosions the total momentum before is zero. [ is positive]

Before After

If we look at the example above we can see that the whole system is not moving, so the momentum before is zero. After the explosion the shell travels right with velocity v₂ and the cannon recoils with a velocity v₁.

The momentum of the system is given as:

So the equation for this diagram would be:

But remember, v₁ is negative so: