Answer: Digital photo albums can be stored digitally therefore you cannot physically and you can have more photos. A good hard drive that has a lot of space is can expensive
if it were to be digital then you would be able to carry it around where ever and look at it to remind you of the memories, however it probably wouldnt last as long as the physical one. eg if you phone breaks there is a chance to restore the photo but you would had to have backed it up beforehand.
There will not be enough momentum from the first hill to cross another hill if he same or larger size because of the way potential energy and kinetic energy works it will not be able go as high as it could go on he fist hill.
