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प्रश्न
A machine is 75% efficient’. What do you understand by this statement?
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उत्तर
If a machine is 75% efficient, it means that 75% of the work input to the machine is obtained as the useful work output. The remaining 25% of the work input has been lost in overcoming the friction.
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संबंधित प्रश्न
Name six simple machines. Give an example of each machine.
Answer the following.
What is a machine?
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)?
Can a simple machine act as a force multiplier and a speed multiplier at the same time?
Classify the following as a lever, a pulley and an inclined plane:
Nutcrackers
Classify the following as a lever, a pulley and an inclined plane:
Scissors
The ______ in the centre, the ______ on one side and the ______ on the other side make a lever of the second order.
Which machine will you use to do the following work? Write their type.
To cut vegetables.
Which machine will you use to do the following work? Write their type.
To draw water from a well.
A pair of scissors is a _____ multiplier.
