The difference between free fall and total weightlessness

First, the nature is different.

1. Free fall.

It refers to the movement of a conventional object with zero initial velocity only under the action of gravity.

2. Complete weightlessness: the apparent weight of the object is zero, that is, when the object is in free fall, if the weight is weighed, it is 0.

Second, the main features are different.

1. Free fall: When the object starts to fall, it is stationary, that is, the initial velocity v=0. If the initial velocity of the object is not 0, it cannot be considered free fall, even if it falls vertically.

During the fall, the object is no longer subjected to any external force (including air resistance) except by gravity.

or the resultant force of an external force is 0.

2. Complete weightlessness: all of its gravity provides the downward acceleration of the object The object in the satellite does the same circular motion as the satellite.

Gravity (gravitational force.

Acts as a centripetal force.

At this point, the object is in the satellite as if there is no gravity (in fact, gravity is still there), and it can be stationary relative to the satellite without the support force (the apparent weight is 0).

Free fall is when an object falls only by gravity with an acceleration of g. There is no muzzle velocity.

The total weightlessness refers to the situation where the acceleration in the vertical direction is g, and the object can also be subjected to other forces, and the number of forces required by the free fall is more than the total weightlessness.

The premise of free fall is that the initial velocity is 0, the acceleration is g, free fall is a kind of motion, which is called free fall motion or the object does free fall motion, and the second is a state of complete weightlessness, and the object in free fall is in a state of complete weightlessness. When the object is completely weightless, it is only affected by gravity in the vertical direction, such as free fall and flat throw, which is simply the relationship between inclusion and containment.

Free fall is more stable and safe! It's dangerous to be completely weightless!

An object in free fall is in a state of complete weightlessness, but it will only fall freely if gravity is present. Complete weightlessness may be the absence of gravity.

The free fall has an acceleration g, and gravity also acts on; If you are completely weightless, the acceleration is 0, and you want an astronaut to drift in a spaceship.

Answer: A free fall is being in weightlessness.

The acceleration of an object in free fall is a=g, according to Newton's second law mg-f=mg f=0, at this time, the spring dynamometer or the table scale indicates 0, and the object is in a state of complete weightlessness.

I think the meaning of "weightlessness" and "overweight" is relative to the force in equilibrium, and the equilibrium between the upward external force f and the gravitational force g at equilibrium is: f=g; When weightless, the acceleration is downward, so fg, at this time the person feels a lot of "pressure".

The so-called weightlessness is not that it is not subject to gravity, but that the gravity is consumed. The expended gravity becomes downward acceleration.

The phenomenon that the pressure of an object on a support is less than the gravitational force experienced by an object is called weightlessness. That is, the apparent weight is less than the actual gravity, and when the acceleration of the near-Earth object is downward, its actual apparent weight is less than the actual gravity, and we call it weightless.

When an object accelerates downward with acceleration g (free fall), we call it completely weightless.

The state of overweight and weightlessness is not that gravity has disappeared, but that gravity itself has not changed, but that the apparent weight has changed.

When we usually talk about the weight of the object, it refers to the apparent weight, that is, when placed vertically in a balanced state, the magnitude of the spring scale or platform scale is equal to the gravity of the object.

In free-fall motion, take the vertical downward direction as the positive direction.

mg-f=mg

f=0 means that the indication of a spring scale or bench scale is 0 as if gravity is gone.

Overweight: There is an upward acceleration. Weightlessness: There is a downward acceleration. According to Newton's second law, the direction of the resultant force in a certain direction is first judged to determine the direction of acceleration.

Strictly speaking, it is completely weightless, as if there is no gravity.

For example, in the case of the mineral water bottle, when both the bottle and the water are only accelerated downward by gravity.

The water in the bottle has the same velocity and acceleration relative to the bottle and is relatively stationary, as if the water has no gravity.

In the case of a free-fall body, weightlessness occurs only when air resistance is taken into account. When an object is in free fall, it will be subjected to two forces, namely gravity and air resistance. Among them, air resistance is related to the speed of movement, shape, and surface material of the object.

In general, the air resistance experienced by an object is proportional to the square of the speed of the object's motion. Therefore, when the object is in free fall, the velocity reaches a certain value, and the condition of weightlessness can be satisfied. And the condition is exactly when the gravitational force is equal to the air resistance, i.e., mg=kv 2.

where: m - mass of the object, g - acceleration due to gravity, k - air resistance coefficient of the object, v - speed of the object).

BC Pair.

Speed has nothing to do with quality.

Because they start falling freely at the same time, and the acceleration of the fall (gravitational acceleration) is the same, it is caused by .

v g t , s g t 2 , v 2 2 gs can be known bc pairs.

Freefall movement.

1.Muzzle velocity vo 0 2End velocity vt gt 3Drop height h gt2 2 (calculated from VO position downwards) 4Inference VT2 2GH

Note: (1) The free fall motion is a uniform acceleration linear motion with zero initial velocity, which follows the law of uniform linear motion with variable speed;

2) a g gravitational acceleration is smaller near the equator and smaller than flat land in high mountains, in a vertical downward direction).

3) Vertical upward throwing movement.

1.Displacement S VOT-GT2 2End velocity vt vo-gt (g=

3.Useful inferences vt2-vo2 -2gs 4The maximum height of the ascent is hm VO2 2g (from the point of throwing).

5.Round-trip time t 2vo g (the time from the throw to the original position).

Note: (1) The whole process is processed: it is a uniform deceleration linear motion, with the upward direction as the positive direction, and the acceleration is taken as a negative value;

2) Segmented treatment: upward is a uniform deceleration linear motion, downward is a free fall motion, with symmetry;

3) The process of ascent and fall is symmetrical, such as the equivalent reversal of velocity at the same point.

Because they fall at the same time, the speed is the same at any moment (before landing). Therefore a false. Since vt=vo+at, the initial velocity is 0, the acceleration is g, and the time is the same.

Therefore B is right. Since vt 2-vo 2 = 2ax, the initial velocity is 0, and a is all g, so in free fall vt is only related to x, i.e., height h, so the displacement is the same, and vt is the same. So C is right.

The acceleration of any object in free fall is the same, g. Therefore d false.

The motion of a free fall is only related to the acceleration, while the acceleration is the same, the velocity is the same at the same time.

Didn't Uncle Galileo do an experiment on the Leaning Tower of Pisa and lose two balls at the same time, proving that speed has nothing to do with mass in free fall = =.