Abaqus can be used to solve problems using Abaqus/Standard and Abaqus/Explicit. (a) State the equation to be solved in the implicit and the explicit version. (b) What is the main difference between the standard and explicit version of the software, and which method is appropriate for a given problem? (c) In the explicit version the lumping technique of the mass matrix is used. What does it mean and why is it applied? Also, please explain what it means physically.