Hello Ramkumar,
Your understanding is correct. MATLAB Simscape Multibody (formerly known as SimMechanics) is a powerful tool for simulating mechanical systems, which automatically generates and solves the equations of motion for the physical models you create. This process is highly abstracted to simplify the modelling and simulation process, meaning that the software does not explicitly expose the underlying equations of motion to the user in a direct mathematical form.
Simscape Multibody handles the equations of motion internally. It creates these equations based on the physical setup (bodies, joints, forces, etc.) that you define using its graphical interface or through MATLAB code. The software uses a symbolic and numerical computation engine to derive and solve these equations efficiently.
For more information to Simscape Multibody you can refer to the below mentioned documentation by MathWorks:
Hope it helps.
