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प्रश्न
The following belong to which class of lever?
Fore-arm
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उत्तर
First-class of lever
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संबंधित प्रश्न
Which class of lever will always have MA > 1 and why?
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?
A 4 m long rod of negligible weight is to be balanced about a point 125 cm from one end and a load of 18 kgf is suspended at a point 60 cm from the support on the shorter arm.
- If a weight W is placed at a distance of 250 cm from the support on the longer arm to balance the rod, find W.
- If a weight 5 kgf is kept to balance the rod, find its position.
- To which class of lever does it belong?
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?
Human-arm
The following are an example of levers. State the class of lever to which each one belongs giving the relative positions of Load (L), Effort (E), Fulcrum (F):
(i) Scissors (ii) Sugar tongs (iii) Nutcracker (iv) Pliers.
Draw a labelled sketch of a second class lever. Give one example of such a lever.
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.
The length of a nut-cracker is 12 cm. A nut, when kept at a distance of 4 cm from its fulcrum, requires an effort of 100 gf to crack it. What force will be required to crack the nut without using the nut-cracker?
