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प्रश्न
What is meant by simple machines?
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उत्तर
Machines that have only one or two parts are called simple machines. Their structure is easy to understand and use. Examples include the nail cutter, bottle opener, and wheel used to push loads, etc.
संबंधित प्रश्न
Answer the following.
What do you understand by a complex machine?
What is an inclined plane?
Give two examples of inclined plane where it is used to raise a heavy load with less effort ?
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)?
Give scientific reason for the following:
Passengers in a bus are pushed backward when it starts suddenly.
Write an expression to show the relationship between mechanical advantage, velocity ratio, and efficiency for a 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.
Give an example of the following use of a machine to change the point of application of the force.
Classify the following as a lever, a pulley and an inclined plane:
An axe
