You have a seatbelt on, but are not holding yourself particularly rigid. As you go through the curve, you find your head leaning the opposite way from the center of the curve. However, the physics description is a little different. For you to go into the circle with the rest of the car, a centripetal force has to be applied to you. For the car, the centripetal force comes from the static friction of the tires in contact with the road imagine trying to take that curve on an icy road; the car would not turn, but go in a straight line off the road at the same speed, most likely, indicating insufficient centripetal force was applied to it.
It is transmitted to every part of the car by the structural integrity of the vehicle. For you, though, the centripetal force comes through your contact with the car, which mainly occurs on your feet, legs, and behind, up to the shoulder, if you are wearing a shoulder belt. That is where the centripetal force comes which pulls your body into the curve with the rest of the car. But if you are not holding yourself rigid, your next can be pretty squishy. So your head does not "get the message" about going in the circle until a little after the rest of your body is already pulled in.
It stays behind for a moment, with no centripetal force, trying to continue in the straight-line path it was on as Newton's first law of motion says, an object will continue at constant velocity unless a net force acts on it. What finally pulls your head into the circle with the rest of you is tension exerted from the rest of your body through the neck, which does not happen until the rest of your body is already moving into the circle.
So physics says that what appears to be an outward force on your head "centrifugal," or center-fleeing, force is actually your head's inertial response to not having a centripetal force on it until just a bit after the rest of the body does. This is why "centrifugal" force is called a fictitious or apparent force.
It is not really there, but it seems to be. Basically, both are defined by their frame of reference, centrifugal from the center towards the outside, centripetal from the outside towards the inside or center. A couple examples of each type of force may help one see the difference between the two. A centrifugal force example is the mud flying off of a spinning tire, or children being pushed out on a merry-go-round.
The force the children feel is centrifugal force pushing them outward. A common example for centripetal force is the moon or a manmade satellite orbiting the Earth. The force comes from gravity, and is the same force allowing the planets to orbit the Sun.
If an object was being swung around on a rope the centripetal force is the tension in the rope. For a spinning object, the force is provided by internal stress. A car moving along an arc, such as on a racetrack, the centripetal force comes from the friction between the tires on the car and the road. A loop traveled on by a roller coaster is another example of centripetal force. Understanding and applying centrifugal and centripetal force is useful to many problems in society.
Centrifugal force is an inertial force that apparently acts on all objects when viewed in a rotating frame of references. Centripetal acceleration is a property of a moving body that is traversing through a circular path, while the centrifugal acceleration is a property of a circularly moving object, and it is direct outward the circular path.
Centripetal and centrifugal acceleration are properties of objects that are related to the objects having a circular motion. Strohmeier, M. Keller, F. Schwemmer, S. Zehnle, D. Mark, F. Zengerle and N.
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