Answers:

1. Slide the newspaper half way under a closed door and ask the two people to stand on the bit of newspaper on their side of the door.
2. There are twelve (not four).
3. Actually, the ladder will rise with the ship!
4. Dimes are smaller than nickels, so choose the dimes!
5. If they put them all together, there will be one pile.
6. Horse racing.
7. The President.
8. Throw the ball straight up.
9. One. Only the earth has earthquakes.
10. Sleeplessness.

Score:
10 right = You're a master of logic.
8 - 9 right = You're good... really good.
6 - 7 right = Not bad...
4 - 5 right = You need to practice.
2 - 3 right = You did terrible. But there is still hope that you "might" be able to improve with a lot of practice and hard work.
0 - 1 right = Uh oh... someone's pet is walking across the keyboard again... (we sincerely hope)