A ball of mass 0.3 kg is initially moving with velocity v = (2 m/s)i + (1 m/s)j. The ball is hit (very hard!) and breaks into two pieces. The first piece has mass m_{1 }= 0.2 kg and velocity v_{1} = (1 m/s)i and the second piece has mass m_{2 }= 0.1 kg and velocity
v_{2} = (4 m/s)j. What impulse was delivered to the ball when it was hit?
First note the relation between impulse and change of momentum:
I = D p = p_{f}  p_{i}
Before

After 

p_{x} 
p_{y} 

p_{x} 
p_{y} 
0.6 kg· m/s 
0.3 kg· m/s 
Particle 1 
 0.2 kg· m/s 
0 


Particle 2 
0 
0.4 kg· m/s 


Total 
 0.2 kg· m/s 
0.4 kg· m/s 
Now use the results in the table to calculate the impulse delivered to the ball.
Make a sketch showing the two momenta and the impulse.
I_{x} =  0.2 kg· m/s  0.6 kg· m/s = 0.8 N· s
I_{y} = 0.4 kg· m/s  0.3 kg· m/s = 0.1 N· s