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प्रश्न
When we want to use a machine as a force multiplier, which class of lever should we preferably use? Give a simple diagram of such a lever.
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उत्तर
Though we can use either first class of lever or second class of lever, for multiplying force, we should preferably use a second class of lever. This is because the mechanical advantage of the second class of lever is always greater than one. A simple diagram of the second class of lever is shown alongside. The wheelbarrow, the bottle opener, and the mango cutter are some of the practical forms of the second class of lever.
संबंधित प्रश्न
Name a machine to obtain gain in speed ?
Write down a relation expressing the mechanical advantage of a lever.
Give one example of a class I lever where mechanical advantage is more than one ?
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.
Which type of levers have mechanical advantage always more than 1? Give reasons.
The following belong to which class of lever?
Sugar tongs
The following belong to which class of lever?
Fore-arm
Shears, used for cutting metals and scissors used for cutting clothes are both examples of levers of the first order. However, whereas the shears always have short blades and long handles, the scissors often have blades much longer than the handles. Explain, why this is so?
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.
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.
