A 9 kg box is placed on a 6 m tall shelf. What will be the kinetic energy of the box right before it hits the ground? (use g = 10 m/s/s)

The illuminance of a surface varies inversely with the square of its distance from the light source. if the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters, by how many meters should the distance of the surface from the source be increased to reduce its illuminance to 30 lumens per square meter?