1. The problem statement, all variables and given/known data A lorry of mass 20,000kg is travelling at 20.0m/s towards a car of mass 900kg travelling at 30m/s towards the lorry. What is the magnitude of the total momentum? 2. Relevant equations m1u1+m2u2=p1 Not sure about any others :\ 3. The attempt at a solution The lorry has a momentum of 400,000Ns in the positive direction and the car has a momentum of 27000Ns in the negative direction but this is before impact. Not sure how to go about this, any help would be appreciated.