Question: Fifty is my first, my second is the third in fourth, and my end is the end of an ending. With a nut I become a nut that isn't, and without one I move.
Answer: Lug. Roman numerals for fifty is L, the third letter in fourth is U, and the end of ending is G. With a nut is Lug nut, which is a nut in one sense, but isn't a nut like an almond. Without nut Lug has a similar meaning to tug, which is moving stuff.
Question: Your father is a scientist who has invented a red pill which, if eaten with 1 blue pill which he has invented, will grant immortality. The night he invents it, he gives you 2 red and 2 blue pills just in case one of them is lost or substandard. He also warns you that an overdose will cause the opposite effect and kill you instead. You put the pills in your pocket and leave his lab for home. On the way home, you are abducted by aliens who blindfold you and throw you into a singularity. At this point, you remember the pills your father gave you. You take them out (you can move and have enough oxygen in space for a short time), but realize that you can't tell the red pill from the blue pill. Even if you take off your blindfold, you can't see anything due to your proximity to the black hole. Given the circumstances, how do you successfully eat 1 red and 1 blue pill and survive?
Answer: Eat half of each pill.