I’ll offer the opinion that blindly using a calculator without understanding why it works is a bad idea, both in that it is likely to lead to engineering mistakes and it cheats you out of important foundational knowledge that enables the tackling of more-complicated problems.

The most fundamental property of permanent-magnet DC motors is their *linear torque-speed curve:*

The above plot is called a *motor curve*. Learn them, love them, internalize them - they are one of the most important design tools you will encounter in FRC. The x-axis is motor speed. The yellow line represents motor torque.

As speed increases, torque decreases linearly, and vice-versa.

As power is proportional to the product of speed and torque, a little bit of math (hint: look at the behavior of the function f(x)=x(1-x)) reveals that the power is a quadratic function of motor speed (and also of motor torque), and peaks at 50% of free speed (equivalently, 50% of stall torque).

In general, it is good practice to design your mechanisms to place your motor loads on the “rising side” of the power curve - that is to say, less than 50% of stall torque (equivalently, greater than 50% of free speed). This ensures that if you have made a mistake or there is a disturbance and your load increases from what you have calculated around, the motor will output *more* power, not less.

There is an additional concern: current draw is proportional to motor torque. The stall current of a CIM is *exceedingly* high - not only will a stalled CIM almost certainly trip the 40A breaker in short order, but due to the limitations of the FRC battery it will almost certainly not actually be able to ever draw full stall current or output full stall torque. In general, you want to keep current draws fairly low; for a CIM, a good rule of thumb is to never design around more than 40A continuous draw (~30% of stall current/torque) unless you’re sure you know what you’re doing.