1. If i went back in time and killed my grandfather, what would happen?
There are a lot of theories about how time works, so I really don't know.
But I think of it this way: Scenario 1: You theoretically take someone into the future where an event has happened (the specifics don't matter), and leave them there. Then you change the future somehow so that that event never happens. They would seem that they're lost in time and don't exist. But if you went back in time to stop yourself from taking the person into the future, then you created a new paradox, and created a new path for time to travel.
Scenario 2: You take someone into the past to meet themself. The future them would not remember meeting the past them, but the past them would remember meeting the future them when they would be brought to the past by you. So that creates a different path for time to travel.
So if you went back in time to kill your grandfather, he would die and you could continue living, because you could still go back in the past before you killed him and stop yourself, thus allowing him to survive.
2. Can God create a boulder so huge that he himself cannot lift it. (answer even if you are not religious please)
I'm agnostic, so I'll take a shot.
No, He cannot, because if He did, He could be able to make Himself be able to lift it anyways. He's supposedly omnipotent, remember?
3. When an unstoppable, unbreakable force meets an unmovable, unbreakable object, what happens?
The unstopable force would hit and reflect/refract off of the immovable object; technically the unstopable object is still moving, and the immovable object is still standing.
OR The immovable object moves and the unstopable force stops.
4. If M&M's only melt in your mouth and not in your hand, what happens if you put your hand in your mouth while holding the M&M?
Your hand melts in your mouth
Or, it's a terrible marketing phrase and should not be trusted.
According to the laws of heat and energy, the m&m has to melt in your hand after a certain period of time.
5. Can you remember to forget something you were supposed to remember?
I can't remember the answer.
Well I guess remembering to forget something is the equivilent to just simply forgetting. If someone told you "forget this, you'll need to remember it later", you could forget it, and thus remembering to forget somehting you were supposed to remember.
Try your best to answer, please. My life is in your hands, guys....