Making moving easier

a)
 Below are a number of simple machines which people use every day. Draw a line to match the type of simple machine to the machine that is used by people. (One of the machines used by people is not needed.)
 

Simple machine
 
      
Machine used by people
 
Lever   •    
•
 Nuts and bolts  
Ramp   •
 
 
  
•
 Windmill  
Wheel   •    
•
 Stairs  
Screw   •    
•
 Table  
     
•
 Garden spade  
b) Ian needs to move a large rock to the middle of his garden. He is going to use a metal bar and a block of wood as a lever to move this rock. He has a choice of 3 metal bars and a block of wood. The bars are exactly the same except for how long they are. The lengths are  1/2 m, 1 m, 1 1/2 m, and 2 m.
  i)
Which metal bar should he choose to use? (circle one) 
(A)   1/2 m         (B)   1 m          (C)   1 1/2 m          (D)   2 m
 
  ii) Draw in the box below how he would set up the metal bar and block of wood to move the rock.

Metal bar           Block of wood