Centrifugal force is the force that tries to push an object out of the circular motion. We encounter the centrifugal force very frequently in our daily lives. This force is encountered only during circular motion. This force tries to push us off the path due to inertia. Examples of centrifugal force include any situation where we drift off a turn or where something is thrown off in a circular motion like in the case of mud flying off the tires of cars.
Examples of centrifugal force:
- Pottery
- Gravitron
- Centrifuge machine
- When a turning vehicle skids off the road
- Centrifugal clutch
- Water does not spill in a vertical spin
- The ellipsoid shape of the earth
- Wall of death
- Mud flying off the tires of vehicles
- Spin-coating
1. Pottery
Image by marcelkessler from Pixabay
Pottery is an art that depends on frictional force and centrifugal force. A potter puts a lump of clay at the center of a flat wheel. The wheel is rotated at high speeds. The centrifugal force will push the clay outward, forming a round shape. The frictional force between the hand and the clay shapes the pot, along with the centrifugal force.
2. Gravitron
Image by Jakob Strauß from Pixabay
Gravitron is a ride that is present in most amusement parks. It uses the laws of centrifugal force to give a thrill to the person enjoying the ride. Basically, it is like a merry-go-round where each cabin/seat is attached to a disk above using strings. When the disk rotates in a circular fashion, the seat is thrown out of the circle but is held safe by the strings that support the seats. As the speed increases the riders have a feeling of being in the air due to the centrifugal force which keeps the riders turning at an angle vertically. All the safety instructions should be followed before taking the ride.
3. Centrifuge Machine
Image by Alberto2018 from Pixabay
A centrifuge machine is a device that uses centrifugal force components or different phases of a liquid. Generally, the gravitational force is used for separation but is very time-consuming and may not work in some cases. Centrifuge machines can be used to separate even small micro- or nano-sized particles when done at high speeds. The formula for centrifugal force is mv2/r. So the centrifugal force is directly proportional to the mass and square of velocity. This force makes the particles with higher mass settle down at the bottom and the lighter objects will come up on top. Plus, since the centrifugal force is directly proportional to the square of velocity, the higher the speed, the better the separation.
Centrifugal machines are widely used in research laboratories. They are also used in nuclear plants, the dairy industry, and the pharmaceutical industry. Washing machines are also an example of a centrifuge machine that uses centrifugal force to ensure maximum cleaning.
4. Spin coating
Another example of centrifugal force is Spin-coating is a technique to deposit thin-film coatings on substrates with controlled thickness. It is a very crucial step in the semiconductor industry. Commonly dip-coating or doctor blade techniques are used but it is very difficult to control the thickness and uniformity of coating.
In spin coating, a precursor solution on the substrate is spun at high speeds. A small amount of the liquid is placed at the center of the substrate. When the substrate is spun the liquid moves in all directions radially due to centrifugal force and coats the substrate uniformly.
The thickness of the thin film can be controlled by adjusting the angular speed. The higher the angular speed thinner will be the film. We can verify this by looking at the formula for centrifugal force. The centrifugal force is directly proportional to the square of velocity. Therefore higher speed the molecules will move farther and result in a thin film. You can watch the videos in this article for more information.
5. When a turning vehicle skids off the road
You might have noticed that many vehicles skid off roads while turning. This is due to the centrifugal force that pushes the vehicle out of the road. This happens when the vehicle is unable to balance the forces. The inertial force of the vehicle tries to maintain the vehicle in a straight path according to newton’s first law. So, when the vehicle turns the centrifugal force pulls the vehicle outwards which is balanced by an inward frictional force and centripetal force. When the frictional force decrease may be due to rain or some other factors, then the forces become unbalanced. In such a case of an unbalanced force, the vehicle will skid.
To overcome such scenarios roads are often banked to ensure safe turns at even high speeds. The angle of backing provides an extra centripetal force to balance the outward centrifugal force. This is not an example of centrifugal force but a good application of it.
6. Centrifugal Clutch
A centrifugal clutch uses centrifugal force to connect the transition shaft and drive shaft of the engine. There is no need to operate the gear to start or stop the engine. It operates based on the centrifugal force generated by the driving shaft, so it engages and disengages automatically. When the speed of the drive shaft crosses a limit the output shaft will be engaged automatically. The output shaft disengages when the drive shaft speed goes below the limit but the centrifugal clutch will not allow the engine to stall. Centrifugal clutches are widely used in go-karts and lawnmowers.
7. Water does not spill out of the bucket in a vertical circle
You might have noticed that when we move a glass of water quickly, the chances of water spilling out decrease defying the laws of gravity. This looks like magic, but there is physics working behind it. Even though gravity will try to pull the water off the bucket, the weight of the bucket is balanced by centrifugal force which pushes the water into the bucket.
8. It is assumed that the ellipsoidal shape of the earth is due to centrifugal force
You might have noticed that when we watch a baseball match in slow motion, the shape of the ball changes slightly due to the many forces acting on it. Similarly, for an object moving in a circular motion, the centrifugal force acts against the centripetal force and as a result, there can be a change in shape. If the centrifugal force is greater then the object will move off the circular path. So, it is assumed that in the case of our planet Earth, the ellipsoid shape is due to the centrifugal force.
9. Wall of death
Wall of death is a carnival show where a vehicle moves across an almost vertical wall in a cylindrically shaped track. The car is able to move vertically defying the laws of gravity due to the centrifugal force. Such stunts cannot be performed under linear motion. That is why the driver uses circular motion to generate the centrifugal force to climb up the wall. Never try these stunts, these are performed by experienced professionals.
10. Mud flying of a tire
You might have noticed mud flying off the tires of vehicles on a rainy day. Some cars have mud-guard to stop them from being thrown off on the other vehicle. The mud sticks onto the surface of the tire without any strong chemical bonds. As the wheel beings to rotate, the centrifugal force pushes tries to push the mud off the wheel. Since the bonding is weak, the forces become unbalanced, and the mud flies off of the tire.
Is the washing machine an example of centrifugal force?
Yes, the washing machine uses centrifugal force to enhance the cleaning action. The centrifugal force removes the dirt off the clothes just like mud flying off the tires. The extra force acts against the chemical bonding of the dirt and removes it off from the clothes.
Is centrifugal force involved in hammer throw?
Yes, hammer throw is also an example of centrifugal force. The person does many revolutions before throwing the hammer. This action increases the speed and hence the centrifugal force. Initially, the centripetal force is provided by the tension of the chain, but as the person releases the hammer the forces become unbalanced, and the centrifugal forces cause it flies off in a specific direction.
See also
Banking of roads
Examples of centripetal force
Centrifugal force
Differences between centripetal and centrifugal forces
Centripetal force
