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प्रश्न
The diagram shows the use of a lever.

- State the principle of moments as applied to the above lever.
- Which class of lever is this? Give an example of this class of lever.
- If FA = 100 cm, AB = 90 cm, calculate the minimum effort required to lift the load.
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उत्तर
(i) Sum of the clockwise moments about the fulcrum is equal to the sum of the anti-clockwise moments about the fulcrum.
(ii) Lever of class III,
Example: forceps or a pair of tongs.
(iii) E × 100 = 190 × 20
∴ E = 38 N.
संबंधित प्रश्न
State the principle of a lever?
A man uses a crowbar of length 1.5 m to raise a load of 75 kgf by putting a sharp edge below the bar at a distance 1 m from his hand.
- Draw a diagram of the arrangement showing the fulcrum (F), load (L) and effort (E) with their directions.
- State the kind of lever.
- Calculate:
- load arm,
- effort arm,
- mechanical advantage and
- the effort needed.
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.
Which class of lever found in the human body is being used by a boy when he raises the weight of his body on his toes?
The following belong to which class of lever?
A see-saw
The following belong to which class of lever?
An oar of a boat
The following belong to which class of lever?
Sugar tongs
The following belong to which class of lever?
A pair of scissors
The diagram below shows a lever in use.

(i) To which class of lever does it belong?
(ii) If FA = 40 cm, AB = 60 cm, then find the mechanical advantage of the lever.
A lever is used to multiply the force.
