Only the Spell card Darkness Approaches can flip a monster into face-down Attack position. By discarding two cards, Darkness Approaches lets you flip one face-up monster face-down without changing the battle position (so a monster may end up in face-down Attack position).
A monster can't manually change battle position on the turn it declared an attack, but it can still be flipped face-down by an effect. Golem Sentry can attack, then activate its effect in main phase 2 and flip itself face down.
Assuming the defending monster is also in attack position, both monsters will be destroyed.
Yes. If your monster is in attack position and you attack a monster that has more attack points than yours, your monster is destroyed and you take Battle Damage to your Life Points equal to the difference between your opponent's monster's Attack Points and your monster's Attack Points.
A monster in face-down Attack position is unable to declare attacks. It can be flipped or Flip Summoned, both actions will switch it into face-up Attack position. It can also have its battle position change by the controlling player, switching it from face-down Attack position to face-down Defence position.
Your monster is destroyed if the monster you attack is in attack position, and you lose life points.
If you switch it from attack position to defence position you can't because no monster can attack from defence position except from "Total defence shogun". But if you switch it from defence position to attack position then you can attack
A monster can't manually change battle position on the turn it declared an attack, but it can still be flipped face-down by an effect. Golem Sentry can attack, then activate its effect in main phase 2 and flip itself face down.
No, a 'Flip Summon' is a manual change from face-down defence to face-up attack position in one of your main phases. If the monster is flipped from an attack, or by an effect, then this is a Flip, but not a Flip Summon. Therefore regular Flip Effect monsters like Night Assailant will trigger from being attacked, but monsters that require Flip Summoning like Guardian Sphinx will not.
There is only one card capable of putting a monster into face-down attack positon; Darkness Approaches.A monster in face-down attack position can't declare an attack, and when Flip Summoned, goes into face-up attack position.
Assuming the defending monster is also in attack position, both monsters will be destroyed.
Yes. If your monster is in attack position and you attack a monster that has more attack points than yours, your monster is destroyed and you take Battle Damage to your Life Points equal to the difference between your opponent's monster's Attack Points and your monster's Attack Points.
It depends.If the Monster declares an attack or already attacked and it is switched to defense position by a card effect (like Enemy Controller or Book of Moon for example) the Monster's position cannot be changed by you, the controller, because it declared an attack already. A Monster's position cannot be changed by their controller for the rest of a turn after they declared attacked with it.If the Monster did not attack yet this turn and their position is changed due to a card effect, it can be changed by the controller.
A monster in face-down Attack position is unable to declare attacks. It can be flipped or Flip Summoned, both actions will switch it into face-up Attack position. It can also have its battle position change by the controlling player, switching it from face-down Attack position to face-down Defence position.
As long as that monster has not declared an attack, or manually changed battle position already that turn, or was summoned on the turn, then yes. If you'd just summoned the monster, or declared an attack with it, or changed it from defence to attack position, then if Book of Moon or Enemy Controller is used, then you can't manually change that monster's position until your next turn.
Yes if you wait a turn
Your monster is destroyed if the monster you attack is in attack position, and you lose life points.
No the attack would not happen because they would no longer have a monster in attack position to attack with.