1.1. Zorbing is an activity which involves a person running inside an inflatable ball, called a ‘zorb’.  Two zorbs, A and B, collide head on with each other, as shown in Figure 1.  The total mass of zorb A and its occupant is 75 kg and the total mass of zorb B and its occupant is 60 kg.  Before the collision, zorb A is travelling at 2.0 m s^-1 and zorb B is travelling at 1.5 m s^-1. 

Figure 1

Calculate:   

(i) The momentum of zorb A before the collision    

(ii) The momentum of zorb B before the collision 

(iii) The total momentum of both zorbs before the collision. 

1.2. After the collision both zorbs bounce off each other and move in opposite directions, as shown in Figure 2.  Zorb A travels at 0.8 m s^–1 and zorb B travels at 2.0 m s^–1. 

Figure 2

Calculate: 

(i) The momentum of zorb A after the collision 

(ii) The momentum of zorb B after the collision 

(iii) The total momentum of both zorbs after the collision.

1.3. Calculate:           

(i) The total kinetic energy of the zorbs before the collision 

(ii) The total kinetic energy of the zorbs after the collision.

1.4. State whether: 

(i) Momentum is conserved during the collision of the zorbs 

(ii) Kinetic energy is conserved during the collision of the zorb 

(iii) The collision of the zorbs is elastic or inelastic.