It strains credulity to believe that you could have such trouble with such a simple concept and you have made assertions that deny Newton's 1st law in addition to arguing against definitions, in addition to making repeated simple math errors and insisting the errors are in others' understanding. Going around in circles and refusing to accept Newton's first law and good explanations is why your first thread was closed. You are doing the same thing again.this reply is a prejudiced one.In this thread ,i never denied anything.I just want to know what are the factors controlling the contact period.Or in other words,is the given datas not enough to find the force?
As I stated in my post above, you need to know the initial and final momentum and duration of the collision. From this you can calculate the average force*. Did you not read that part?what are the other datas required and how it is contributing to the force?