If 4 kg block is held after 2 s of start then how high 2 kg block will rise from the beginning before coming to rest momentarily?

velocity acquired by each block after 2 s is v=2g3Height attained by 2 kg in 2 s,At the instant the 4 kg block is held, the 2 kg block has attained a velocity of 2g/3 and this block will continue to move upward with constant retardation 'g'. So the further rise of 2 kg block till it comes to rest is given byh2 = V2 / 2g = (2g/3)2 / 2g = 2g / 9.The total height = h1 + h2 = 2g / 3 + 2g / 9= 8g / 9