Believe it or not gravity is not really a force, it is an acceleration and on Earth it is about 32 feet/sec2. This same science principle applies in decelerating devices like parachutes and parafoils. The parachute decelerates or slows down the fall of the object.
What is a .DS_Store or ._ AppleDouble file? .DS_Store files are created by OS X to store metadata about folders and files including viewing options, icon positions and color labels. ._ AppleDouble files are created by the OS X when an application adds resource data or metadata to a file on a disk whose format doesn't support resources or metadata.
Thumbs.db is a file which holds thumbnail versions of the pictures in that folder. If you delete it, nothing serious will happen. It is safe to delete. In fact, the next time someone opens that folder Windows will recreate that thumbs.db file. Just be careful. Not all files are as safe to delete as that one. â¢