Complex sentence: The force gain grows exponentially with the coefficient of friction,\\ mu\\,, the number of turns around the cylinder, and the angle of contact,\\ phi\\,, measured in radians.
Split into simpler sentences: The force gain grows exponentially with the coefficient of friction,\\ mu\\,, and the number of turns around the cylinder. Actually it depends on the angle of contact,\\ phi\\,, measured in radians.