42.a screw is a special kind of simple machine? It is a
C. inclined plain Edge
D. wheel and axle

43.A man with a wheelchair wants to get inside a building, what simple machine will help him get inside the building easily?
A slides
B. Pulley
C. ramp of the building
D. stairs of the building

44. A can opener is a combination of which simple machines?
A. a lever and a wedge
B. wedge and a screw
D.an inclined plane and a wedge

45. Which of these is an example of a wedge?
A wheel
C. seesaw
B. spoon
D. butter knife

46. Which of the following is an example of inclined plane?
A. plier
C. scissors
B. stairs
D. nut cracker

47. In a construction site, how do workers transport mixed cement and hollow blocks from the ground floor to the 2nd floor?
A by using a wedge
B by using a pulley
C. by using a screw
D. by using a wheel and axle​