Motivation: http://what-if.xkcd.com/ is awesome. While reading it, I've noticed that some of the articles begin with a court answer that Randall then elaborates on. And I wondered what would happen if you removed everything but the questions and answers.
Q: What if everyone who took the SAT guessed on every multiple-choice question? How many perfect scores would there be?
Q: How many model rocket engines would it take to launch a real rocket into space?
A: About 65,000
Q: When - if ever - will the bandwidth of the Internet surpass that of FedEx?
Q: What if you somehow managed to make a stereo travel at twice the speed of sound, would it sound backwards to someone who was just casually sitting somewhere as it flies by?
Q: How hard would a puck have to be shot to be able to knock the goalie himself backwards into the net?
A: This can’t really happen.
Q: Could a high-speed train run through a vertical loop, like a rollercoaster, with the passengers staying comfortable?
Q: When (if ever) did the Sun finally set on the British Empire?
A: It hasn't
Q: If you had a printed version of the whole of (say, the English) Wikipedia, how many printers would you need in order to keep up with the changes made to the live version?
A: This many:
Q: How fast can you hit a speed bump while driving and live?
A: Surprisingly fast.
Q: If winds reached 500 mph, would it pick up a human?
Q: When, if ever, will Facebook contain more profiles of dead people than of living ones?
A: Either the 2060s or the 2130s.
Q: I was absentmindedly stirring a cup of hot tea, when I got to thinking, "aren't I actually adding kinetic energy into this cup?" I know that stirring does help to cool down the tea, but what if I were to stir it faster? Would I be able to boil a cup of water by stirring?
Q: How much of the Earth's currently-existing water has ever been turned into a soft drink at some point in its history?
Q: What height would humans reach if we kept growing through our whole development period (i.e. till late teens/early twenties) at the same pace as we do during our first month?
Q: If a T-rex were released in New York City, how many humans/day would it need to consume to get its needed calorie intake?
A: About half of an adult
Q: What if we were to dump all the tea in the world into the Great Lakes? How strong, compared to a regular cup of tea, would the lake tea be?
Q: Is there any way to fire a gun so that the bullet flies through the air and can then be safely caught by hand? e.g. shooter is at sea level and catcher is up a mountain at the extreme range of the gun.
Q: Astrophysicists are always saying things like "This mission to this comet is equivalent to throwing a baseball from New York and hitting a particular window in San Francisco." Are they really equivalent?
Q: If you made a beach using grains the proportionate size of the stars in the Milky Way, what would that beach look like?
A: Sand is interesting.
Q: Has humanity produced enough paint to cover the entire land area of the Earth?
A: This answer is pretty straightforward.
Q: Assuming that you have a spaceship in orbit around the Earth, could you propel your ship to speeds exceeding escape velocity by hitting golf balls in the other direction? If so, how many golf balls would be required to reach the Moon?
A: It depends how good your swing is.
Q: How far would a tungsten countertop descend if I dropped it into the Sun?
A: Not very far.
Q: At what speed would you have to drive for rain to shatter your windshield?
Q: What took more energy, the building of the Great Pyramid of Giza or the Apollo Mission? If we could convert the energy to build the Great Pyramid, would it be enough to send a rocket to the Moon and back?
Q: Could you get drunk from drinking a drunk person's blood?
Q: As plastic is made from oil and oil is made from dead dinosaurs, how much actual real dinosaur is there in a plastic dinosaur?
A: I don't know
By reading this, you have expressed an irrevocable agreement to interpret this post as a joke, not as a mockery against Randall Munroe's fine work. You have also agreed to look up all the references and read all the other what if posts as well as the XKCD comic.
I would like to thank Randall for his wonderful comics and writings.