Important Questions on Simple Machines
What is a pulley? Name its different types. 
Define an inclined plane. Give two uses of inclined planes. Give two examples each of a wedge, and a wheel and axle arrangement. What is an ideal machine and what is its efficiency? Why is this not achievable in practice? Define the three kinds of levers. Draw diagrams to show the position of the fulcurum, load, and effort in each of them. Differentiate between a single fixed pulley and a single movable pulley. List four steps to be taken for proper care of machines. Explain how it is possible for a thin child to lift a heavy child on a seesaw. 
