Final answer:
The kinetic energy of the second ball just before it hits the ground is 100 J.
Step-by-step explanation:
The kinetic energy of the second ball just before it hits the ground can be determined by understanding the conservation of energy. Since both balls are thrown at the same speed and there is no air friction, the kinetic energy of the second ball just before it hits the ground would be the same as the first ball, which is 100 J.