History of simple machines

Take a look at the video about simple machines (s.m) and answer

• How many parts has a simple machine got?
• What have humans created with s.m?
• What do s.m do?
• List the 6 main s.m.
• Which is the oldest s.m?
• Which is the most simple s.m.?
• How long have s.m.been being used?
• Why are simple machines called so?
• Who made the first simple machine? How old are they?
• How do we define and measure Work?
• Which s.m. is easiest to build?