We know that during fragmentation (explosion) of any material the particles possess equal Kinetic motion which is given by the formula
In the first particle , m=2 kg ,v= 3 m/s
* 2 * 3² J
*2 * 9 J
= 9 J
In the second particle let the required velocity be v.
The kinetic energy of both particles need to be equal.
Ans:The velocity of the piece of 1 kg is √18 m/s.