Wheel and Axle

Introduction

A machine which consists of a wheel attached to a small axle so that both of them (the wheel and axle) rotate together, and in this process force is transferred from one to another: this is defined as the wheel and axle machine. The axle is supported by a thing or a bearing which allows rotation. A small force which is applied from the wheel can amplify large loads attached to the axle. This is looked as the version of the lever. A drive force is applied tangentially to the perimeter of the wheel and a load force is applied to the axle. These two are balanced around a hinge which is known as the fulcrum. 

Wheel Axle

Wheel-axel machine is a simple machine which makes tasks easier in terms of force by applying the concept of mechanical advantages. wheel and axle is assembly formed by two disks, or cylinders, of different diameters mounted together so that they can rotate together around the common axis and the thin rod that needs to be turned is called the axle and the wider object fixed to the axle, on which we are apply force is called the wheel. A tangential force applied to the periphery of the large disk can exert a larger force on a load attached to the axle thus achieving the mechanical advantage. Also the wheel and axle does not dissipate or store energy, because it has no almost no friction as well as elasticity,thus power output at the axle equals to the input by the force applied to the wheel. 

Mechanical Advantage

Machines make our work easier to do. We use several machines in our daily life to make our work easier. Mechanical  advantage is basically when we put a small amount of energy and a huge amount of work is done by that small energy. Being specific,  it’s the ratio of force that the machine produces which is the output, to the force which is put into the machine by humans which is also known as the input. The wheel and axle comes under the category of six simple machines that are lever, pulley, inclined plane, wedge and screw. We try to use the simple machines because they give us the mechanical advantage. For example if we carry weights in our arms we will definitely feel burdened than carrying on a cart which moves on wheels. The axle and wheel are two circle-like structures that rotate together for the work to be done. The force is transferred from the axle to the wheel in most of the cases. It’s the ratio of radius of the wheel to the radius of the axle. Note- the radius is the half of the diameter and the diameter goes from the middle of the circle touching both the ends of the circle.it crosses through the origin or the midpoint of the circle. Although radii is used in the calculation of the wheel and axle but we can also do it with the help of the diameter of wheel and axle, it provides us with the same result.

Since the wheel and axle system rotates around its own bearings, thus the points on the circumference, or edge, of the wheel move faster than points on the circumference, or edge, of the axle. Therefore, a force applied to the edge of the wheel must be less than the force applied to the edge of the axle, since power is the product of force and velocity .Thus if a and b be the distances from the centre of the bearing to the edges of the wheel A and the axle B and If the FA (input force) is applied to the edge of the wheel A and the force FB  at the edge of the axle B is the output, then  a/b is the ratio of the velocities of points A and B is given by , so the ratio of the output force to the input force, or mechanical advantage is given by