See the video.
See the sketch as per my video. The ball weight is 400 gram Distance from fulcrum of tube 0.35 meter The ball is resting 1 meter Now use pythagoras equation to calculate exact distance of ball. It will be 1.060 m. Now use torque formula Torque= rf=rmg So torque of ball is 0.400*1.060=0.424 So counterweight will be only 424 gram to Balanced the seesaw. But I took 500 gram to take advantage of heavy counterweight. So seesaw will be tilted . Now if I am releasing the ball from 1 meter height and it will travelled 2 meter. Calculate bthe kinetic energy. Mgh=0.400*10*2=8 Joule And counterweight will be rotate more than 180 degree and device will get back it's initial position and ball again fall down anti clockwise. Two lock and Spring based latch pin will work to hold the device and ball. I am interested in impact energy of ball.if ball fall down and compressed a spring after each stroke and spring release it's energy at the time of falling down of Ball then? The reason is that the ball will have to lift up only 24 gram weight As counterweight is 424 gram so the will do two work at first it will work to balance the seesaw then the energy will work to lift up only 24 gram weight. This is the main reason of overunity.