I am new to the forum. I was calculating the force losses in a seat belt pretensioner. Here is the question. A cylindrical plastic rod is pushed on one side at a force of 6367.2 N inside a metal tube. Find the energy loss (force loss or final force or output force) due to the compression of the rod. Given Initial pressure = 670 bar Initial force= 6367.2 N Original length of rod= 177 mm Changing length of rod = 37.80 mm Rod material = plastic Youngs modulus of rod= 1.8 GPa Inner dia of tube = 11 mm Dia of rod = 9.6 mm Please help.