A particle is projected from a point 𝐴 with velocity 𝑢√2 at an angle of 45° with horizontal as shown in figure. It strikes the plane 𝐵𝐶 at right angles. The velocity of the particle at the time of collision is

Question : A particle is projected from a point 𝐴 with velocity 𝑢√2 at an angle of 45° with horizontal as shown in figure. It strikes the plane 𝐵𝐶 at right angles. The velocity of the particle at the time of collision is