yes they also need to knock and state that it is the police
Enter for what? To do what? For what reason? Question is too broad to answer. You need to state more specifics. no they cant enter your house without your permission unless they have a warrant
Police can use reasonable force to enter a property with a warrant. However, unless it's a no-knock warrant the police will generally give you approximately 15 seconds to come to the door before they force entry.
Not unless they have a valid reason, like if they can see something suspicious without searching the house yet.
Police with an arrest warrant can enter the home of the person named in the warrant if they have reasonable grounds to believe he is on the premises. They can search the premises in any place the accused person would be able to hide (they couldn't for example, look in the drawers of a nightstand, because no one could hide there). Police have to get a search warrant to enter the house of a person other than the one named in the arrest warrant.
the police have power to enter your house if they have a warrant.warrants are given by special people in high places and if they gain this warrant they have reason to believe you have something illegal in your house,e.g drugs,guns,evidence for a crime,etc.
If the Police have a warrant to search your property, they have the right to forcibly enter your house if admittance is not granted. The same goes if they have an arrest warrant for you and you refuse to come out. They may also have that right if there is a crime in progress. If there is a high speed chase after subjects who the police witnessed committing crimes and the suspects enter someone's house, the police have the right to enter. Or if someone is holding you hostage in your home, the police can forcibly enter. They may also have that right if they have probable cause to believe you are in immediate danger or deceased.
no no
if they find illegal drugs or a unregistered gun in your car they can have permission to enter your home for the reason they have met you for
It depends on where you went with the warrant.
Define "bust" in. If they know you are in there, yes, they may enter - especially if it is what is known, in some jurisdictions, as a "forthwith" warrant.
No, they need to verify that there is no one in the residence that is in need of assistance.
Yes. They need a warrant unless you give them permission to enter. It does not matter if you know the person or not, they either need a warrant or your permission to enter your house to search for anything including a person.