[quote]I wonder how I can unzip the file.[/quote]
You should be able to unzip downloaded ZIP file with any unzip program (do a google search if you do not have one.) and window system also provide unzip function.
[quote]I need Physics simulations on Kinetic Energy for my presentation. [/quote]
I do not know what you really need because you did not describe it in detail.
There are many simulations in this forum. Please find the one fit your need.