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प्रश्न
What do you understand by a machine?
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उत्तर
A machine is a device that allows us to do work with less effort. Machines make our work easier to do. Machines have made our lives comfortable and faster.
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संबंधित प्रश्न
When is work said to be done by a force?
Can a machine have an efficiency of 100%? Give a reason to support your answer.
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.
Classify the following as a lever, a pulley and an inclined plane:
A knife
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.
Rearrange the letters and find out the name of the tool.
R L E V E
| ______ | ______ | ______ | ______ |
A pair of scissors is a _____ multiplier.
