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प्रश्न
Define Efficiency
उत्तर
Efficiency: Efficiency of a machine is the ratio of the useful work done by the machine to the work put into the machine by the effort. In other words, it is the ratio of the work output to the work input.
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संबंधित प्रश्न
Name six simple machines. Give an example of each machine.
State if the following statement is true or false. Correct the statement if it is false.
Work done by a machine is always more than the work done on a 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.
Fig. shows a spade. It is being used to lift soil weighing 30N from the ground.
(a) Mark the direction of the least force on the handle necessary to keep the spade balanced.
(b) Calculate the least force on the handle necessary to keep the spade balanced (the weight of the spade is negligible).
(c) If the left hand was move towards the soil on the spade, would the force on the handle necessary to keep the soil balance the greater or less? Give a reason for your answer.
(d) To which class of lever does the spade belong?
What is the relationship between the mechanical advantage and the velocity ratio for:
(i) An ideal machine,
(ii) A practical machine.
Establish a relationship between efficiency, M.A., and V.R.
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.
Classify the following as a lever, a pulley and an inclined plane:
A knife
Which machine will you use to do the following work? Write their type.
To remove the lid of a tin.
Which machine will you use to do the following work? Write their type.
To draw water from a well.
