So for a two wheel shooter, a few things change. 1] The ball is not "rolling" on the wheel. If both wheels are rotating at equal speed, the ball does not spin at all. So, instead of the ball's exit velocity being half the surface speed of the wheel, the exit velocity is equal to the surface speed of the wheel up until the point that it begins slipping. At 4:07, Sam mentions that 2*V_b = V_f. In the case of a two wheel shooter, replace this with V_b = V_f, and then carry out the same process. 2] Since you have more wheels, you need to calculate the total inertia of the entire wheel system. If you have two stages of wheels, different wheels may have different moments of inertia. If there is a gear or belt reduction between them, each wheel may roll at a different speed, so each may contribute a different amount to the inertia of the ball. Let us know if you have any further questions! Best, Sid

So for a two wheel shooter, a few things change. 1] The ball is not "rolling" on the wheel. If both wheels are rotating at equal speed, the ball does not spin at all. So, instead of the ball's exit velocity being half the surface speed of the wheel, the exit velocity is equal to the surface speed of the wheel up until the point that it begins slipping. At 4:07, Sam mentions that 2*V_b = V_f. In the case of a two wheel shooter, replace this with V_b = V_f, and then carry out the same process. 2] Since you have more wheels, you need to calculate the total inertia of the entire wheel system. If you have two stages of wheels, different wheels may have different moments of inertia. If there is a gear or belt reduction between them, each wheel may roll at a different speed, so each may contribute a different amount to the inertia of the ball. Let us know if you have any further questions! Best, Sid