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प्रश्न
The following belong to which class of lever?
A fire tongs
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उत्तर
Third-class of lever
संबंधित प्रश्न
What is a lever?
Draw a diagram of a lever which is always used as a force multiplier. How is the effort arm related to the load arm in such a lever?
Fig 3.17 below shows a lever in use.

(a) To which class of lever does it belong?
(b) If FA = 80 cm, AB = 20 cm, find its mechanical advantage.
(c) Calculate the value of E.
A lever of length 9 cm has its load arm 5 cm long and the effort arm is 9 cm long.
- To which class does it belong?
- Draw a diagram of the lever showing the position of fulcrum F and directions of both the load L and effort E.
- What is the mechanical advantage and velocity ratio if the efficiency is 100%?
- What will be the mechanical advantage and velocity ratio if the efficiency becomes 50%?
The following belong to which class of lever?
An oar of a boat
The following belong to which class of lever?
A pair of scissors
The following belong to which class of lever?
Knife
In the following diagram of a wheelbarrow, mark the fulcrum (F) and indicate the directions of load (L) and effort (E) with arrows.

What class of lever is it? Give one more example of the same class of lever.
State the types (or kinds) of lever, and give two examples of each kind.
A crowbar of length 100 cm is used to lift a load of 5 kgf. It has its fulcrum at a distance of 20 cm from the load. Calculate:
(i) the mechanical advantage of a crowbar and,
(ii) the effort applied at the other end.
