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Question
Name the three classes of levers and state how are they distinguished. Give two examples of each class.
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Solution
Three classes of levers are:
(a) Class I levers or first-order levers:
Examples are:
 |
 |
| See Saw | Scissors |
Between the effort and the load is the fulcrum.
[Ratio of M.A. and V.R.] for levers in this class can be any value between one and one, either more or less than one. They can multiply forces.
(b) Class II levers or second-order levers:
Examples are -
 |
 |
| Lemon squeezer | Wheel Barrow |
Between effort and fulcrum is load, with the effort arm always longer than the arm. These levers' M.A. and V.R. are always greater than 1.
(c) Class III levers, or third-order levers:
Examples are
 |
 |
| Plucker or Fire Tong, (Sugar Tongs) |
Foot Treadle |
Always place effort between fulcrum and load. The effort arm is always shorter than the load arm. These levers' M.A. and V.R. are consistently less than 1.
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RELATED QUESTIONS
Describe three orders of levers giving an example of each. Draw neat diagrams showing the positions of fulcrum, load, and effort in each kind of lever.
Give one example of a class I lever in a case where the mechanical advantage is less than 1?
Name the class to which the following lever belong:
an oar rowing a boat.
The diagram given below shows the three kinds of levers. Name the class of lever and give one example of the class.
Draw diagram to illustrate the position of fulcrum, load, and effort, of the following:
a see-saw.
In a lever, the fulcrum is at one end at a distance of 30 cm from the load and effort is at the other end at a distance of 90 cm from the load. Find :
(a) the length of load arm,
(b) the length of effort arm, and
(c) the mechanical advantage of the lever.
Tick the most appropriate answer.
A pair of scissors is an example of a/an
Classify the following into levers:
Wheel barrow
A ______ lever will always have M.A. > 1.
Classify the following into levers:
Sugar tongs
