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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
Select the correct alternative:
For an ideal machine, the efficiency is
What do you understand by a simple machine?
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.
Write the relation between mechanical advantage, velocity ratio and efficiency.
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)?
Define Simple machine
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.
What is the efficiency of a machine?
A uniform metre scale is kept in equilibrium when supported at the 60 cm mark and a mass M is suspended from the 90 cm mark as shown in the figure. State with reasons, whether the weight of the scale is greater than, less than or equal to the weight of mass M.
Name the levers mentioned in the following passage. Identify the fulcrum, load, and effort of each and say which type of lever it is.
Ravi and Savita sit on a seesaw in a garden. In the meantime, a gardener is trimming trees in the garden. He puts the leaves and other garbage in the wheelbarrow. Later, Ravi gets thirsty and he buys lemon sherbet. The sherbet seller cuts the lemon and squeezes it using a lemon squeezer. He puts small pieces of ice in the glass with the help of the tongs.
