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प्रश्न
State whether the following statement is True or False.
A boy does work while pushing a wall.
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उत्तर
This statement is false.
Explanation:
In physics, work is defined as force multiplied by displacement. Pushing a wall requires using force, yet the wall does not move (displacement is zero), hence the labor done is zero.
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संबंधित प्रश्न
State if the following statement is true or false. Correct the statement if it is false.
There are four types of simple machines.
Derive the relationship between mechanical advantage, velocity ratio and efficiency of 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)?
What is the efficiency of an ideal machine?
What is the efficiency of a machine?
Classify the following as a lever, a pulley and an inclined plane:
A slide
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 hold a papad for roasting it.
Why is this so traveller’s bags have wheels?
The idea of a simple machine originated with the Greek philosopher Archimedes.
