i bought a 1994 honda accord and it was running fine then all of a sudden when i put it in reverse the engine started to shake and it looks like my ball bearings fell it can u tell me what the problem is

It sounds like your hydrolic motor mount, they have a bad habit of breaking and need to be replaced often.

most likely you got bad rear engine mount. if your accord is automatic you got rear mount with vacuum assist, if it manual its a regular rubber mount.
if yours is automatic i would check all vacuum hoses and solinoids in vacuum assistance.
if manual i would jack engine up (slightly), just to take weight of engine off mount, and check mounts for cracks and hardings.
i don't know if that would be easy to do, but i know to replace rear engine mount you need to remove intake manufold.

mine did that...if the rear one is out..then the front one might be gone. those rear ones arent cheap. i changed my rear and front and now it doesnt vibrate. pull up the e brake hard and then start the car..have someone shift gears (automatic) and watch the engine..if its severley moving then look at the mounts...if the back is bouncy..then u know ur rear is out....

u can also tell if the rear is out if u look down and see some brown hydrolic fluid around it. really those arent easy to replace.

check the front mount by exposing the inside with a screwdriver...if nothing is there then its gone...thats 60 bucks.