Two blocks of masses `3kg` and `6kg` rest on a horizontal smooth surface. The `3kg` block is attached to a spring with a force constant `k=900 Nm^(-1)` which is compressed `2m` from beyond the equilibrium position. `3kg` mass strikes the `6kg`mass and two stick together-
A. velocity of the combined masses immediately arter the collision is `10 ms^(-1)`
B. velocity of the conbined masses immediately after the collision is `5ms^(-1)`
C. Amplitude of the resulting oscillation is `sqrt2 m`
D. Amplitude of the resulting oscillation is `sqrt5//2m`
