Gravity real or not real?

Question

If we are going around a corner in a fast car, we feel like we are being thrown outward, we call it outward centrifigal force. But in terms of Newton's laws this false force doesn't exist. Can you explain why?

Hint. start with Newton's first law.

Answer 1

Centrifugal force can be either real or ficticious.

A real or "reactive" centrifugal force occurs in reaction to a centripetal acceleration acting on a mass. This centrifugal force is equal in magnitude to the centripetal force, directed away from the center of rotation, and is exerted by the rotating object upon the object which imposes the centripetal acceleration in accordance with Newton's Third Law of Motion.

A pseudo or "fictitious" centrifugal force appears when a rotating reference frame is used for analysis. The (true) frame acceleration is substituted by a (fictitious) centrifugal force that is exerted on all objects, and directed away from the axis of rotation.

Both of the above can be easily observed in action for a passenger riding in a car. If a car swerves around a corner, a passenger's body seems to move towards the outer edge of the car and then pushes against the door.

In the reference frame that is rotating together with the car (a model which those inside the car will often find natural), it looks as if a force is pushing the passenger away from the center of the bend. This is a fictitious force--not an actual force exerted by any other object. The illusion occurs when the reference frame is the car, because that ignores the car's acceleration. A number of physicists treat it much as if it were a real force, as they find that it makes calculations simpler and gives correct results.

However, the force with which the passenger pushes against the door is real. That force is called a reaction force because it results from passive interaction with the car which actively pushes against the body. As it is directed outward, it is a centrifugal force. Note that this real centrifugal force does not appear until the person touches the body of the car (ignoring any force exerted by the seat on the person's body, etc). The car also exerts an equal but opposite force on the person, called "centripetal force".

Answer 2

Centripetal force (P) is the real force according to many physicists. Centrifugal force (C) is but the equal and opposite force of Newt's Law 3.

For example, as you push the pedal to the floor and go around that curve, you fly out of the car and lend in a ditch along side the road. No? Why not? Because P = C and the net force acting on your body behind the steering wheel is f = ma = P - C = 0. There is no net force on your body because C is equal and opposite to P. Newt's Law.

The real force, centripetal, is the push inward towards the center of the rotation (turn) by you seat cushions, seat belt, and side of the door. In other words, there is some physical thing pushing you into the center of the turn. The faux force, centrifugal, is the equal, but opposite reaction to that push.

Why does your car push you in towards the center of turn...because of Newt's Law 1. As you turn, your inertia wants you to go in a straight line (Newt's Law 1), but the car pushes you into that curved path. When there is a push, there is a force.

In fact, p = mv; where p is momentum (related to inertia), m is your mass, and v is the velocity (not speed) you are traveling in the car. Thus, by Newt's Law 1, so long as v = constant (including zero), momentum remains fixed and whatever direction m was going will stay the same.

But the car turn forces your velocity to change over time; that is, dv/dt <> 0, which is the change in velocity. So look what happens to p. Now we have dp/dt = m dv/dt = ma because a change in velocity is acceleration. And old ma = f the net force acting on your body, Newt's Law 2 and the centripetal, real, force.

In the case of an orbiting satellite, for example, the real thing pulling the satellite towards the Earth, changing the velocity vector, where the center of the orbit is, is gravity. Gravity is real and it's really pulling at that satellite.

Answer 3

By Newton's first law, the occupants of the vehicle would move in a straight line when the vehicle turns. The force applied is actually toward the INWARD part of the curve, by the vehicle, causing the occupants' path to curve in the same direction as the vehicle. However, since the occupants' frame of reference is rotating as they turn with the vehicle, they PERCEIVE a force OUTWARD. The perceive outward force is just their intertia, which must be counteracted in order to keep occupants and vehicle together.

Answer 4

You and your car are separate objects acting upon each other. You can feel this directly in a variety of ways - for example, when you accelerate your car has to push on you to get you up to speed (which you feel as being pushed back into your seat). An object retains the motion or lack thereof that it has until something else pushes it. If your car didn't push you, it would go and you'd just fall out, I guess.

The same thing happens when you turn a corner. If you think about it, the process of turning means reducing your speed in the former direction to zero and increasing your speed in a new direction to whatever speed you are travelling at. A turn, then, requires changes in velocity a.k.a. acceleration.

Like when you speed up, you feel this acceleration as being pushed in one direction or another. The reason you NEED to be pushed is because otherwise inertia would just keep you going in the same direction (as we see a lot in movies...).

Answer 5

ummm, are you extreme ? cuz this appears like a shaggy dog tale. sometimes I nonetheless unsure while every physique is rather stupid, or purely joking. there's no distincion in gravity between macro and micro. The regulations of gravity are the comparable for each merchandise. the factor is, that there are 2 diverse regulations. Newtons regulation became the 1st one, that's a greater convenient sort, and nonetheless used for common initiatives. the different is Einsteins typical relativity concept, which takes different factors into consideration, like time. What ever formulation you gonna use, it doe snot remember, in case you're speaking relating to the earth orbiting the sunlight, or human beings leaping in the air. Its the comparable stress doing the comparable factor.

Answer 6

The common misconception, believed by many physics students, is the notion that objects in circular motion are experiencing an outward force................................read more here, also explains it with newtons laws