X-CUBE-SPN7, 6Step_Lib.c

Three questions regarding MC_SixStep_Ramp_Motor_calc()

1.) What unit do the mechanical acceleration rate parameters/variables have? (apparently not 1/min/s or rad/s²)

2.) 'mech_accel_hz = SIXSTEP_parameters.ACCEL * Rotor_poles_pairs / 60' - so 'mech_accel_hz' is rather the electrical acceleration than mechanical?

3.) I found that MCM_Sqrt() takes 1,3 .. 1,8 ms (32 MHz CCLK) while the (ARM-MDK) math library's sqrt() takes 150 .. 250µs. What is the benefit of using 

MCM_Sqrt()

Thanks for comments.