Helping the past from present knowledge

If you were transported back in time to, lets say, 1000CE or even 1500CE, how much of the 2008 knowledge could you explain? How many machines could you rebuild? How useful could you be as a person from the future? How much of your world could you explain to them? How different do you think you would be from them in your knowledge and belief system?

Could you explain to them:

  1. Our monetary/banking system?
  2. Our social structure and who is really in charge in 2008?
  3. Our understanding of the solar system and the universe?
  4. The major advancements or science in the past 100 years?
  5. Basic knowledge on the human body?
  6. How the modern car, train and planes work?
  7. How our phone, TV, Microwave over, cell phone work?
  8. What a computer is and does in term they would understand?

Could you build:

  1. A rudimentary transportation device with a steam engine?
  2. A telegraph to help them communicate?
  3. A telescope, miscroscope or sextant?
  4. A crane to help them build?