How to explain the phenomenon of weightlessness and overweight in physics

If an object is at rest, the supported force is equal to the gravitational force, as we all know, the force is the factor that changes the state of motion of the object, when he moves upwards at a uniform speed, the pulling force or support force is also equal to its gravitational force, when he wants to accelerate, the pulling force or supporting force should be used as a part of the driving force for acceleration in addition to counteracting gravity, so the force received at this time is greater than the gravitational force, which is called overweight. Weightlessness is similar in that it can be understood as a downward force when the supporting force is equal to the gravitational force. The support force is less than the gravitational force at this point.

Overweight phenomenon: When there is an upward acceleration of the object, the phenomenon that the pressure of the object on the support (or the pulling force on the suspended object) is greater than the gravitational force of the object itself is called the phenomenon of overweight and weightlessness: when the object has a downward acceleration, the phenomenon that the pressure of the object on the support (or the pulling force on the suspended object) is less than the gravitational force of the object itself is called the phenomenon of weightlessness.

An object is overweight when it has an upward acceleration, weightless when it has downward acceleration, and completely weightless when it has a downward acceleration g. This can be linked to the experience of taking an elevator, when the elevator accelerates up, it will feel an upward thrust, which is overweight, and when the elevator accelerates down, it will feel light and fluttering under your feet, which is weightlessness.

Weightlessness, for example, if you sit in an elevator, there is an electronic scale in the elevator, and you stand on it, when the elevator accelerates down, the indication becomes smaller, because your gravity provides its own acceleration, and when the elevator accelerates up, you have to receive additional support from the elevator to provide you with acceleration, so the indicator becomes larger. Got it?

1.Overweight phenomenon

Definition: The phenomenon of overweight is said when the pressure of an object on a support is greater than the gravitational force on an object.

Cause: The object has an acceleration in a vertical upward direction.

2.Weightlessness

Definition: The phenomenon of weightlessness is when the pressure of an object on a support (or the pull force on a suspended object) is less than the gravitational force on an object.

Cause: The object has a vertical downward acceleration.

3.Complete weightlessness

Definition: A situation in which the pressure of an object on a support is equal to zero, i.e., there is no interaction with a support or hanging object in contact with it.

Cause: The acceleration of an object vertically downward is the acceleration of gravity, that is, it is only affected by gravity and will no longer interact with supports or hanging objects. Whether or not complete weightlessness occurs is independent of the direction of motion, as long as the acceleration of the object vertically downward is equal to the acceleration due to gravity.

[Are overweight and weightlessness the increase and decrease in the weight of an object?] 】

A: No, it is not. The gravitational force of an object can only be measured with a spring scale in equilibrium, because the force (or pulling force) that the spring scale supports on the object is equal to its gravitational force.

If the system has acceleration in the vertical direction, then the indication of the spring scale is not equal to the gravity of the object, when it is greater than mg, it is called overweight and less than mg is called weightlessness (when it is equal to zero, it is called complete weightlessness).

Note: The object is overweight or weightless, and the Earth's gravity acting on the object is always present and does not change in size. The phenomenon of overweight or weightlessness occurs with objects'The velocity v direction is independent and only depends on the direction of the object's acceleration.

In the state of complete weightlessness (a=g), all physical phenomena normally generated by gravity disappear completely, such as a single pendulum stalling, objects immersed in water are not buoyant, etc.

In addition, the state of overweight or weightlessness can be explained by the independence of Newton's second law, which means that each force acting on an object produces a corresponding acceleration. The gravitational force of the object in the above state always exists, and the magnitude does not change, and the acceleration (commonly called gravitational acceleration g) produced by it does not change, and the natural gravitational force does not change.

1. Overweight: g+ma.

Derivation of the formula: f (support force) -mg = ma.

Conclusion: Upward acceleration and downward deceleration: the acceleration direction is upward, resulting in overweight. Therefore, as long as the acceleration direction is upward, it is overweight, regardless of the direction of velocity.

2. Weightlessness: g-ma.

Derivation of the formula: mg-f (support force) = ma

Conclusion: Downward acceleration and upward deceleration: the direction of acceleration is downward and weightlessness is generated.

Conditions under which overweight and weightlessness occur:

1. The conditions for the occurrence of overweight phenomenon: when the object accelerates upward or decelerates downward, the object is in an overweight state, that is, no matter what direction the object moves, as long as it has an upward acceleration, the object is in an overweight state.

2. Conditions for the occurrence of weightlessness: when the object accelerates downward or decelerates upward, the object is in a weightless state, that is, no matter what direction the object moves, as long as it has downward acceleration, the object is in a weightless state.

Definition of overweight and weightlessness.

1. Overweight: The phenomenon that the pressure of the object on the support (or the pulling force on the suspension rope) is greater than the gravity of the object is called overweight.

At this point there is FN = mg + MA.

2. Weightlessness: The phenomenon that the pressure of the object on the support (or the pulling force on the suspension rope) is less than the gravitational force on the object is called weightlessness.

At this point there is FN = mg + MA.

1. Overweight: When the object has an upward acceleration, the pressure of the object on the support (or the pulling force on the hanging object) is greater than the gravity of the object itself.

2. Weightlessness: When the object has downward acceleration, the pressure of the object on the support (or the pulling force on the suspended object) is less than the gravity of the object itself.

3. Complete weightlessness: when the object accelerates vertically downward or decelerates vertically upwards with acceleration a=g (free fall motion, vertical upward throwing motion), the pressure of the object on the support (or the pulling force on the suspended object) is equal to zero.

Acceleration ascent and deceleration descent are both acceleration upwards and are overweight;

Deceleration rise and acceleration fall are both acceleration direction downward, which is weightlessness.

Overweight: The phenomenon that the restraining force on an object, also known as the elastic force (pulling or supporting), is greater than the gravitational force on the object. When the object is in an upward acceleration motion or a downward deceleration motion, the object is in an overweight state, that is, no matter how the object moves, as long as it has an upward acceleration, the object is in an overweight state.

Weightlessness: A state in which an object moves freely in a gravitational field without exhibiting weight or less weight, also known as zero gravity. Weightlessness is sometimes referred to in terms of zero-gravity and microgravity environments. To be precise, it is weightless when the acceleration is straight downward.