A man standing on a still boat jumps out horizontally with a speed of \(20~\text{m/s}\) with respect to the boat. If the mass of the man is \(70~\text{kg}\) and that of the boat is \(210~\text{kg},\) then the speed of the boat after the man jumps will be:
1. \(20~\text{m/s}\)
2. \(6.67~\text{m/s}\)
3. \(5~\text{m/s}\)
4. \(15~\text{m/s}\)