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प्रश्न
What is a lever?
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उत्तर
A lever is a simple machine consisting of a rigid rod that is capable of turning around a pivot called a fulcrum. It has three parts, namely effort, load, and fulcrum.
- Fulcrum: The rod of the lever rests on it and the lever rotates about it.
- Load: The weight lifted by the liver is called the load.
- Effort: The force applied on the other end of the rod to lift the load is called the effort.
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संबंधित प्रश्न
A crowbar of length 120 cm has its fulcrum situated at a distance of 20 cm from the load. Calculate the mechanical advantage of the crowbar.
What is an inclined plane?
Write an expression for the mechanical advantage of an inclined plane in terms of its length I and vertical height h.
Fig show a system of four pulleys. The upper two pulleys are fixed and the lower two are movable.

(i) Draw a string around the pulleys. Also show the place and direction in which the effort is applied.
(ii) What is the velocity ratio of the system?
(iii) What is the mechanical advantage of the system?
(iv) What assumption do you make in arriving at your answer in part (iii)?
Comment on the statement ‘The mechanical advantage of a machine is greater than 1’. Give an example of a lever mechanical advantage is:
(i) greater than 1.
(ii) Equal to 1.
Classify the following as a lever, a pulley and an inclined plane:
An opener
Classify the following as a lever, a pulley and an inclined plane:
An axe
The ______ in the centre, the ______ on one side and the ______ on the other side make a lever of the third order.
Which machine will you use to do the following work? Write their type.
To hold a papad for roasting it.
Identify and mention the types of simple machines.
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| ______ | ______ | _______ |
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| ______ | ______ | ______ |






