A rod of length ' ', having mass '
' and ends '
' and '
' is lying on a horizontal plane. A particle of mass '
' attached to end '
' with a massless string of length '
', equal to the length of the rod.

If the mass of the particle is also ' ' and it is given velocity '
' perpendicular to the rod. Then the acceleration of the centre of mass, just after projecting the particle will be ______

For the rod:
Observing the motion of the particle from end ' '

As, the particle is performing circular motion about the end ' $x$ '.