25 Contact Forces Examples in Everyday Life

If while applying force to an object, the user makes any kind of direct or indirect contact with the object’s body, then such a force is known as a contact force. This implies that for a contact force to exist there must be a point of contact between two or more objects. Contact force is also known as direct force as in the case of contact force the object is in direct contact with the source of the input force. Primarily, there are four types of contact forces in nature, namely, push and pull force, tension force, the force of friction, and upthrust.

Examples of Contact Forces

There are a variety of daily life activities and applications that make use of the concept of contact forces. Some of the examples of such activities and applications are given below:

1. Hitting a Ball with Bat

The application of the concept of contact forces in real life can be observed easily by watching a player play games such as baseball, cricket, tennis, golf, etc. In either of the listed games, the player tends to hit a ball with the help of a bat. When the bat strikes the surface of the ball, the force and energy possessed by the bat get transferred to the ball. As a result, the ball advances in the direction of the applied force.

2. Pulling a Zipper

To open or close a zipper or a zip fastener, the user is required to hold the structure of the device and apply an adequate amount of pull force to it. Since the user is required to make contact with the device to transfer force, such a device can be listed under the category of applications that demonstrate the use of contact forces in real life.

3. Spinning Top

A spinning top is a game object or toy that tends to exhibit a rotatory motion when it is spun around either manually or with the help of an automatic mechanism. To spin the toy around, the user is required to hold the spinning top in a particular position and apply force to it. This implies that the mode of the application of force, in this case, is direct, hence spinning top forms yet another example of applications that use contact forces in real life.

4. Pushing or Pulling a Block

The force required by a person to push or pull an object is generally applied to the surface by making direct contact with the object, hence it forms yet another example of contact forces in real life.

5. Rolling a Ball on the Ground

Rolling a ball on the ground is a prominent example of contact forces in real life. Here, the application of contact forces can be seen in two phases. In the beginning, when the user throws or kicks the ball onto the ground, the ball begins to roll. After some time, the ball comes to rest. It can be observed easily that the user is required to make contact with the object with his/her hand or with his/her foot to make it roll over, hence the mechanical force applied to the ball acts as contact force. Likewise, the force of friction offered by the ground as an opposition to the movement of the ball also exists at the point of contact between the ball and the ground, thereby forming yet another example of the application of contact force.

6. Tug of War

Tug of war is a game in which the players tend to form two teams that stand in open space against each other in a straight line. A straight line is generally marked on the ground that denotes the two courts of the teams. All the players are provided with a thick rope that is generally made up of jute material. A ribbon is tied in the middle of the rope and the ribbon portion of the rope is held right above the central line marked on the ground that separates the two teams. The main aim of the game is to pull the ribbon tied on the rope completely towards either side of the playing court. The team that manages to pull the rope and drag the ribbon towards their side is declared the winner of the game. The application of contact force in real life can be observed easily while watching the players play the tug of war game.

7. Opening or Closing the Lid of a Jar

To open or close the lid of a jar, a bottle or any other container, the user is required to hold the base of the jar with one hand, the lid of the jar with the other hand and apply twist force to the jar in a clockwise or anti-clockwise direction. This particular force applied to the lid of the jar is yet another example of a contact force.

8. Motion of a Pendulum

A pendulum is nothing but an arrangement of a heavy metallic bob or ball and a string. Here, the metallic bob is attached to the one end of the string, while the free end of the string is attached to the base of a horizontal frame in such a way that the bob is allowed to hang freely in the air. The mechanical push force applied by the user that is required to set the pendulum bob into motion is one example of contact forces in real life, while the air resistance offered to the motion of the pendulum is another example of the contact forces acting on the pendulum bob. This is because both types of forces tend to act on the surface of the pendulum object by making a point of contact.

9. Kneading the Dough

Kneading the dough is a prominent example of daily life activities that help display the concept of contact forces. This is because to knead a dough the user is required to make repeated use of push and pull forces and both push and pull forces can be applied to an object only by making a point of contact.

10. Inflated Balloon

The force exerted by the air molecules on the inner surface of the balloon is a classic example of a contact force.

11. Ship

A ship is able to float on the surface of the water due to its precisely designed structure and the action of balanced force on the surface of the boat. The gravitational pull of the earth tries to pull the boat towards the centre of the earth, while the upthrust provided by the water pushes the boat in the upward direction. Both gravitational force and upthrust force possess the same magnitude and act on the ship in opposite directions. Here, the upthrust provided by the water tends to act as a contact force, while the gravitational pull of the earth acts as a non-contact force. This is because the upthrust force exerted by the water necessarily needs to act on the surface of the boat; whereas, the gravitational force is universally present and does not require any kind of contact with the object in consideration, which in this case is the ship.

12. Lifting Objects

Lifting objects such as a bucket full of water, gym weights, baggage, or any other object that has mass requires the user to make a point of contact with the object and then apply an adequate amount of mechanical force to it, thereby forming yet another example of contact force in real life.

13. Leaning Against the Wall

Leaning against the wall appears to be an activity that does not require application of any force; however, even to lean against a wall, a collective action of multiple forces is usually required. For instance, the body of the person leaning against the wall tends to exert a push force on the surface of the wall. The wall in response to the push force exerted by the body of the individual tends to exert an equal magnitude reaction force in opposite direction of the action force, i.e., onto the body of the individual. The push force exerted by the wall and the body during the process tend to act on the surface of the object and therefore, is known as contact or direct force.

14. Picking Fruits and Vegetables

Picking up fruits and vegetables from the garden is yet another example of the everyday activities that involve the application of direct or contact forces.

15. Drawing Water from Well

The process of drawing water from a well basically makes use of a pulley system. The pulley system of the well contains a freely rotating wheel attached to a rigid frame fixed to the edge of the boundary of the well. A rope that is tied to the handle of a bucket is wrapped on the surface of the wheel and is dropped into the well. The user then holds the free end of the rope and pulls it to draw the bucket filled with water out. The force that is required to pull the rope and to hold the bucket is yet another example of contact force.

16. Skating

Roller skating, ice skating, and other activities like riding a skateboard rely on the action of force of friction between the tyres of the skating shoes and the ground, hence such activities tend to demonstrate the contact forces in action in real life.

17. Moulding Clay

Moulding clay is an activity that is generally used by potters to modify the shape of the pottery objects. Also, moulding clay is used as a fun crafting activity for young children in which they tend to form diffrent shape and size objects using playing clay. The process of moulding clay requires the user to apply pressure on to the surface of the clay by making use of the pull or push force. Both pull and push type of forces fall under the category of contact forces, hence moulding clay is a prominent example of the applications that make use of contact forces in real life. Also, the force that the potter use to support the structure of the clay artifact by holding it gently from the inner of the outer surface of the object can be listed under the category of contact forces as the force required to suport or hold the object in shape exerted by the hand of the potter is exerted on the surface of the object, i.e., between the point of contact of the hand and the craft object.

18. Sky Diving

Sky diving is an adventure sport activity in which a person tends to jump from a high point in the atmosphere and land onto the earth’s surface with the help of a parachute. Here, the gravitational pull of the earth tends to pull the sky diver towards the surface of the earth, while the air resistance or the drag force offers opposition to the motion of the diver. The air resistance or the drag force tends to act at the point of contact between the air molecules and the body of the sky diver, hence it is known as the contact force. Similarly, the gravitational pull of earth does not require any sort of point of contact with the object for its implementation, which is why it is called non contact force.

19. Stretching a Rubber Band

A rubber band is basically a loop made up of an elastic material. An elastic band is capable of suffering deformation to a particular threshold value. To vary the shape of an elastic or rubber band, the user holds it in his/her hands and begin to move the hands in opposite directions. As a result of the pull force exerted by the motion of the hands in opposing directions, the band gets deformed. When the user removes the pull force from the rubber band, it tends to regain its original shape. The force used to deform the shape of a rubber band by stretching it is yet another example of contact force in real life.

20. Drilling a Hole in the Wall

Usually, the process of drilling a hole in the wall requires a person to hold the rotating drill attached to the drilling machine against the surface of a wall perpendicularly. The force exerted by the drill machine onto the surface of the wall is definitely an example of contact force in real life as it is applied between the point of contact of the drill bit and the wall. Likewise, the process of driving a nail into a wall manually with the help of a hammer is also another example of the contact force.

21. Tightening and Losening up the Screw

To tighten and losen up a screw, a screw driver is usually attached to the head of the screw and a mechanical force is applied to rotate it in the clockwise or anticlockwise direction. The mechanical force applied by the user at the point of contact of the screw driver and the screw is a prominent example of contact force in real life.

22. Slicing Objects

Slicing object into two or more parts is a classic example of the use of contact force in real life. Generally, to slice an object into two parts, an object with a relatively less surface area is used to exert the pressure on the other object that is to be sliced. The force that is used for this purpose is called shear force that tends to act between the point of contact of the two objects.

23. Clipping Nails

The process of clipping nails requires a clipper object that has two sharp edged blades placed parallel to each other attached to a lever mechanism. The nail is held between the blades of the nail clipper and the lever is pressed. As a result, the force exerted by the blades gets transferred to the nail, thereby causing it to get separated or clipped off. It can be observed easily that the force exerted by the nail clipper on the nail is an example of direct or contact force.

24. Gecko Lizards

Gecko lizards manage to stick to the surface of a wall, a roof, or any other plane surface object with the help of force called van der waals force. This type of force used by the lizards is a form of force of attraction that generally acts between the footpads of the lizards and the surface of the wall, hence it tends to form yet another example of contact forces.

25. Slide

A child sliding off a slide is yet another example of contact force in real life. This is because the force of friction that helps the child slip on the surface of the ramp of the slide tends to act between the surface of the slide and the child’s body.