Introduction
Physics brings to light important knowledge on the rotational motion; moments of force have been applied to design rotating devices that help make work easier in almost every dimension. Moreover, the mere fact that these forces can be calculated makes them controllable and measurable. The rotation of objects is the fundamental theory behind most technologies emerging in the modern world. Almost every particle on earth vibrates about its mean position, the theory of moments have led to the development of efficient movable parts along with their maintenance. This has boosted many industries ranging from motor engine manufacturers to water pumps, among others. This paper will explore torque as a moment of force as well as its real-life applications (Macaulay 13).
Torque
When an object rotates from its fulcrum, several observations are made, its speed, type of force, and such. This object requires some form of force to begin rotating about that point. This force, which enables an object to rotate, is referred to as a Torque. The point of rotation is known as pivot or fulcrum. This rotation can be witnessed in machines such as seesaws, combustion engines, and water taps, among others. Torque is represented as shown in figure 1 below.
Figure 1 above represents a torque, with an object, rotating about an axis O. Let us call the force F, and its distance from the axis which is also known as a pivot, r. It is also imperative to note that r can be defined as the moment arm. Again, r is a vector, which is positive towards the object. Torque is therefore defined as the measure of this force F, which enables the object to rotate. Therefore we can have the equation for torque as follows.
Τ= r x F = r F sin (θ) where
- Τ is Torque
- r is a vector and represents the moment arm
- F is the force
- θ is the angular difference between the force F, and axis O
In essence, as can be observed from the equation above, torque is simply the cross-product of r and F, for example, Torque = r x F. The SI unit of torque is Newton-metre (Note that this unit is usually used to express joules; however, we should distinguish torque from energy as they are vector and scalar quantities respectively). Since the calculation is a cross-product, we can determine the direction of torque. This can be done by placing one’s fingers towards the direction of r and then curling them towards the direction of F and observing the direction of the thumb. This method is known as the right-hand rule.
There are situations wherein more than one force would be applied on the same moment arm, each of these forces will cause torque and there will be as many torqueses as the number of forces acting on the moment arm. Since torque is a vector, torques applied in different directions will cancel out, if they are of the same magnitude or give a resultant if they are of varying magnitudes. The resultant of torques is known as the net torque. When the net torque is Zero then it is called rotational equilibrium (University of Guelph 1).
Real-life applications
Torque is applied in many areas of life, from industries to riding of bicycles, opening of doors and many others. The following are some of the real life applications of torque.
Wenches and Seesaws
This is one of the most common and simple demonstration of torque and its relationship with moment arm, which is the point of balance, and force. In a seesaw, two forces are applied on a long rod pivoted at about its center, on both sides; force is applied by weight of those who sit on it. The resultant force that determines who is heavier depends on the distance from the pivot as well as weight. For instance, if two bodies sit on a seesaw 3m away from the pivot and with weights of 40 and 50 respectively, we can have a resultant force of about 400N on one side and 500N on the other side. This will give 1200NM on one side and 1500NM on the other. Definitely the 500N weight will go down while the other one is lifted. This can change, for example if the 40kg weight moves further to 4m from the pivot, as this will change its vertical force to 1600NM (Colwell 1).
In wenches, the most important consideration lies in its log nut. Even though the force may be constant, it is important to note that moment arm can be manipulated by varying distance from pivot. This theory explains why doors have hinges that are placed as far as practicable from the pivot. Figure 2 below show a representation of a seesaw (Advameg, Inc. 1).
Gyroscopes
Gyroscopes are other devices that apply torque. They contain fly-wheels usually mounted on top of the axle that is placed on a big ring that is perpendicular to moment arm. Once set to spin, they spin in three dimensions which make them very stable and provide them with ability to resist changes that may try to upset their balance. In essence, this improves gyroscopic inertia which suits it for navigational works. Gyroscope eases understanding of torque when right hand rule is employed, since on spinning, torque and angular momentum tend to be at odds. However what fascinates is how these forces align to stabilize the gyroscope. For this to be achieved, conservation of angular momentum is required (Advameg, Inc. 1).
Electric motor
Every electronic device that uses motor as its driver makes use of torque in its applications. This includes household appliances as well as automobile engines. The energy produced in such engines is normally converted to torque so as to enable the car move. The net torque converted depend on the state of that automobile, for instance a starting car would require more torque than a moving one. The engine does this by controlling the number of revolutions which in turn regulate the amount of torque conversions. Furthermore, torque is applied even in automatic engines where torque converter transfers power to the gearbox, from the flywheel. Every electric motor applies torque as in vacuum cleaners and such like. Torque is therefore very essential for complex engines. Other applications of torque include tuning of water tap, cycling, water pump, opening doors, hydraulic press, pulleys, screws, inclined planes, levers and many others (Advameg, Inc. 1).
Conclusion
Torque is an essential part of real life applications. Its appliance ranges from one industry to another as well as in domestic life. It refers to the quantified force that just causes rotation about some axis. Its application varies from gyroscope to motor engines (both manual and automatic); this makes it a central part of mechanical engineering as much as it is in physics.
Works Cited
Advameg, Inc. “Torque-Real Life Applications”. Science Clarified. 2011. Web.
Colwell, Catherine. “Torque: An Introduction”. PhysicsLAB. 2011. Web.
Macaulay, David. “The New Way Things Work”. Boston: Houghton Mifflin, 1998.
University of Guelph. “What is torque?” Physics Department, University of Guelph. 2005. Web.