The maximum height attained by pendulum

Question

A particle of mass m moving with velocity  vº  strikes a simple pendulum  of mass m and sticks  to it . The maximum   height attained  by the pendulum  will be

Answer 1

Let us take that the pendulum is at rest initially and after the collision the velocity of the system is V . Now from the conservation of momentum we have , 

Initial Momentum = Final Momentum 

Now let us take that the block rises to maximum height h. 

So, P. E of the combination = K. E of the combination