i am making a robot with a rotating disk of 8KG and diameter of 1.5 ft . i want to rotate this disc using DC gear motor at a speed of 100 RPM . by my calculation that would require a an output power of 30 W . can someone confirm this calculation ??? it looks wrong to me . also if i use four 30W gear motors of different RPMs namely 100 , 200 , 300 , 400 and use them simultaneously to run the disc will the disc achieve 400 RPM ??? will this assembly work ??? i am building this robot as a hobby to compete in robo war on a local level . if anyone can help i will appreciate it