Answer
55 cm
Work Step by Step
The player jump distance of $55$ cm. The elevator descending with a velocity $v_y$ = 1 m/s and the velocity is constant. Acceleration is zero $a$ = 0. \\
The elevator is in a free fall so no acceleration is exerted and there is no force is exerted on the player when he jumps. The only force is his weight, so the player can jump the same distance as he is on the floor. So, the answer is
$$\boxed{ y = 55 \mathrm{~cm}} $$
