Question

The simple machine used to draw water from a well is a​
(A) Wedge
(B) Axe
(C) Pulley
(D) Screw

Answer 1

Hint: We have to find which simple machine used to draw water from a well. For this we first have to understand the concept of how we pull something.
Also, we will understand how using simple machines can ease our job. So, as we know that to pull anything, we use pulley so we understand the concept of pulley and how it works.
And after that we will distinguish between the given options that can do a job like pulley and after comparison, we can choose the right option.

Complete step by step answer:
The question is we have to select which simple machine is used to draw water from a well, so for this first we need to understand how water is drawn from a well.
When we draw water from a well, we use a rope to draw the water and move the rope towards ourselves. Therefore, if we want to draw water from a well, we have to pull the rope.
But doing this job without a machine is very difficult as it takes a lot of force to lift a rope without a machine. Then the concept of a simple machine comes, these machines are machines that do not contain engines and gears.
Pulley is a simple machine which helps us multiply forces, or used to reduce forces.
If we want to lift a heavy weight, there's only a limited force our muscles can supply, even if we are the world's strongest man. But if we apply a simple machine to do work such as pulley and we can effectively multiply the force where the body produces.
Pulley works on the concept of ‘the more wheels we have, and the more times we loop the rope around them, the more we can lift’.
If we use one-wheel pulley to pull water as shown, it works as: -
 
 If we have one wheel and a rope, a pulley helps us to reverse the direction of our lifting force. So, as in the picture above, we pull the rope downwards to lift the weight upwards. If we want to lift something that weighs 100kg we have to pull down with a force equivalent to 100kg, which is 1000N (newtons). If we want to pull the weight 1m into the air, we have to pull the loose end of the rope a total distance of 1m at the other end.
So, we have seen that by using a pulley we can easily lift an object, so we use pulley to draw water from well.

Therefore, option C is correct.

Note: Always remember that there is a force applied on the rope of the pulley which is called tension and deNote:d by letter T which is equal to the product of mass of the weight and the acceleration of the object.
If the object is in motion, we will use acceleration of the moving object but if the object is in rest, we use gravitational constant \[g = 10\dfrac{m}{{{s^{ - 2}}}}\].
Also remember the formula of acceleration of the whole system, \[a = \dfrac{{Net\,pulling\,force}}{{Total\,mass\,to\,be\,pulled}}\].