The principle of conservation of momentum states that the total momentum of a closed system remains constant if no external forces are acting on it.
In this case, we calculate the total momentum before the collision. The returner has a momentum of \(0 , \text{kg-m/s}\) and the diving player's momentum is \(130 , \text{kg-m/s}\).
To find the total momentum before the collision: \[ \text{Total momentum before} = \text{momentum of returner} + \text{momentum of diving player} = 0 , \text{kg-m/s} + 130 , \text{kg-m/s} = 130 , \text{kg-m/s} \]
According to the conservation of momentum, the total momentum just after the collision will be the same as before the collision:
\[ \text{Total momentum after} = 130 , \text{kg-m/s} \]
Therefore, the magnitude of the total momentum just after the collision is \(130 , \text{kg-m/s}\).
The correct response is: 130 kg-m/s