To move or hold an object in place, a variety of forces or a combination of different forces tend to act on the object with or without making any contact with the surface of the object. The forces that tend to act on an object without making any sort of direct contact with the body of the object are known as non-contact forces. This implies that there exists no point of contact between the object and the source of the force in the case of a non-contact force. Non-contact force is also known as indirect force. Primarily, there are four types of non-contact forces in nature, namely, gravitational force, magnetic force, nuclear force, and electrostatic force. Some other names for non-contact forces include distance force or an invisible force.
Examples of Non-Contact Forces
There are a variety of daily life activities and applications that make use of the concept of non-contact forces. Some of the examples of such activities and applications are given below:
1. Fruits Falling from Tree
When fruits get properly riped, they tend to get detached from the tree branches and drop to the ground. This mainly happens due to the action of gravitational force that tends to pull the fruit towards the core of the earth. Here, the force gets applied to the fruit without coming in direct contact with the object and is known as non-contact force.
2. Attracting Iron Nails to a Magnet
Attracting iron nails to a magnet is a simple demonstration of magnetic force in real life. This particular process of attracting the iron nails towards the magnet is a prominent example of non-contact force as the iron nails get attracted towards the magnet bar even when there exists a distance between the iron nails and the magnetic object.
3. Revolution of Planets around Sun
Gravity or gravitational force is the force of attraction that tends to exist between any two objects that have mass. Gravity is the main force that helps the planets and other celestial objects to revolve around the sun. The action of the force of gravity on the planets and other celestial objects present in the space that causes them to revolve in their respective axis does not require the objects to have direct contact with the source of the force, hence the revolution of planets and other celestial objects around the sun is a classic example of the application of non-contact or direct force in real life. Also, the force by virtue of which the natural satellites or moons present in outer space tend to revolve around their respective planets is an example of indirect force.
4. Charged Comb
A charged comb experiment or activity is a prominent example of the activities that an individual can perform to verify and demonstrate the existence of electrostatic force in real life. To perform such an activity, the user charges the comb by rubbing it against his/her hair and then tends to bring the charged comb close to the uncharged bits of paper placed on a rigid flat surface. As a result, a force of attraction gets developed between the charged comb and the uncharged bits of paper, which causes the pieces of paper to stick to the surface of the comb. Here, one can easily observe that the bits of paper get attracted to the charged comb even when the comb is held at a distance from the paper pieces, thereby indicating the application of non-contact force in real life.
5. Compass
A compass is a device or a gadget that is used to locate directions. Basically, a compass contains a magnetic needle mounted on the top of a pivot. The inside of a compass is properly graduated and the locations are distinctly marked as north, south, east, and west. The needle of the compass tends to point in the North direction. A compass tends to work on the basic principle of magnetism. Magnetism or magnetic force does not require any point of contact with the objects, hence a compass tends to form a prominent example of the objects used in daily life that make use of non-contact forces for their basic operation.
6. Electrostatic Generator
An electrostatic generator is a device or a machine that basically works on the principle of static electricity. When a person touches an electrostatic generator, his/her hair tends to rise upwards and display the effects of electrostatic force. There exists no point of contact between the user’s hair and the device, hence the force generated by an electrostatic generator is another example of non-contact force in real life.
7. Object at Rest
Any object present on the surface of the earth manages to hold its position of rest due to the gravitational pull of the earth. This is the reason why every object resting on the surface of the earth forms a prominent example of the application of non-contact force in real life.
8. Sugar in Plastic or Metallic Container
One can easily visualize the concept of non-contact forces in real life by looking at the sugar containers. Usually, the crystals of the sugar placed in a plastic or metallic container tend to stick to the surface of the container due to the action of electrostatic force existing between the container surface and the sugar crystals. In this case, the electrostatic force that binds the sugar crystals to the walls of the container is a form of indirect force. Such a force also causes the sugar crystals to stick to each other and form small clusters of sugar.
9. Roller Coaster Ride
A roller coaster ride is an amusement park ride that basically consists of a metallic track that contains multiple ups, downs, highs, and lows. The roller coaster train tends to move on the tracks with the help of an electric motor; however, when the vehicle reaches the maximum height of the track, the train engine is turned off and the vehicle is allowed to move on the track with the help of gravitational pull of the earth. The gravitational pull of the earth is an indirect force, hence the motion of a roller coaster ride partially makes use of non-contact force.
10. Door Catch
A door catch is basically a magnetic mechanism that is fixed to the surface of a wall, door, or cabinet. The main purpose of a door catch is to hold the door or the panel of a cabinet to a fixed position. This tends to eliminate the need to shut or hold a door or a cabinet panel open manually. The force that tends to act between the magnetic mechanism of the door catch is completely non-contact or indirect in nature.
11. Magnetic Levitation Trains
The mechanism of a magnetic levitation train makes use of the concept of non-contact forces as the working of such trains primarily depends on the action of strong electromagnets. Such trains tend to eliminate the need for rigid steel wheels as well as track locomotives, thereby simplifying the construction, maintenance, and working of the trains. Since the structure of the train does not interact with the tracks, the action of the force of friction gets eliminated automatically. This is the reason why such trains are less noisy, suffer minimum vibrations, are significantly less susceptible to undergo wear and tear easily, and have a much longer lifespan as compared to the traditional trains.
12. Balloon Party Trick
To perform a balloon party trick, a user is required to rub a balloon against the surface of woollen cloth and bring the balloon close to the tiny bits of paper or hair. Rubbing the balloon against the woollen cloth tends to charge the balloon up, while the bits of paper or the hair remains unchanged in nature. Bringing the charged balloon close to the uncharged particles develops an electrostatic force of attraction between the two objects. As a result, the uncharged particles move in the direction of the charged balloon, thereby displaying the existence of non-contact force in real life.
13. Nylon or Woolen Clothes
One can easily observe and experience the effect of the non-contact force in real life while putting on or taking off nylon or woolen clothes. The crackling sound that one can hear while wearing or removing such clothing from the body indicates the existence of static electricity between the surface of the cloth and the body. The development of electrostatic force does not require a point of contact between the clothing and the body of the wearer, which is why such a daily life activity can be easily listed under the category of the everyday applications that employ indirect forces. A similar type of force due to the triboelectric effect between the dryer drum of a washing machine and the clothes causes the clothes to make a clattering sound when they are removed from the dryer.
14. Television
Another daily life application or gadget that implements and illustrates the concept of non-contact force in real life is a television. One can easily feel a force of attraction between the screen of the television screen and the surface of the skin by moving hands a few millimetres above the surface of the television screen. This particular force of attraction is known as the electrostatic force or static electricity. The static charge between the dust particles moving around the surface of the gadget’s screen mainly exists due to the polarization of the particles. The existence of indirect force between the air molecules, dust particles and the television screen also explains the reason why a new layer of dust gets deposited on the surface of the screen immediately after wiping off the previous layer of dust from the gadget’s screen.
15. Clothes from the dryer
Another daily life application or gadget that implements and illustrates the concept of non-contact force in real life is a television. One can easily feel a force of attraction between the screen of the television screen and the surface of the skin by moving hands a few millimeters above the surface of the television screen. This particular force of attraction is known as the electrostatic force or static electricity. The static charge between the dust particles moving around the surface of the gadgets screen mainly exists due to the polarization of the particles. The existence of indirect force between the air molecules, dust particles and the television screen also explains the reason why a new layer of dust gets deposited on the surface of the screen immediately after wiping off the previous