Focal Charge Torque Calc app focuses on optics, mechanics, electromagnetism and fluid mechanics, integrating five high-precision calculation modules to provide intelligent solutions for scientific research and engineering scenarios: Photo Scale (Using Focal Length): Input parameters such as lens focal length and sensor size, automatically convert shooting angle of view and imaging ratio, and assist in photographic composition and optical system design. Toe Resistance Stress: Based on the pile foundation theory of geotechnical engineering, combined with soil layer parameters and pile body geometry, accurately calculate pile end resistance and stress distribution, and optimize pile foundation bearing design. Surface Charge Density: Based on Gauss's theorem of electromagnetics, input data such as electric field strength and dielectric constant to quickly solve the surface charge distribution density of conductors or dielectrics, which is suitable for capacitor design, electrostatic protection and other scenarios. Mean free path: Integrate the kinetic theory of gas molecules, combine temperature, pressure and molecular diameter parameters, and calculate the mean free path of gas molecules in real time, which helps molecular transport analysis in vacuum technology, semiconductor technology and other fields. Fluid Motor Torque: Based on the principle of fluid mechanics momentum, the flow rate, pressure difference and motor structure parameters are input, and the torque value and efficiency curve are accurately output to support the performance optimization of hydraulic motors, turbines and other equipment. Suitable for optical engineers, geotechnical designers, electromagnetic researchers and fluid machinery practitioners, driving innovation with precise calculations, simplifying the process of solving complex problems, and accelerating the digital transformation of scientific research and engineering.