Why is the velocity of the highest point of vertical upward throwing 0?

It starts to move upwards, but the object is subjected to gravity, and gravity is downward, so the object gradually slows down, decelerates to 0, and then starts to fall downward; It has just started to land, and it is the highest when it has not yet landed, because it has been rising before; At first, the landing becomes no longer the highest, and the landing speed begins to increase, so the maximum speed is 0

In detail: the object can move, so it has kinetic energy, when the starting point, the object has a certain velocity with kinetic energy, the object begins to move upward, due to gravity and resistance, the kinetic energy of the object is consumed, converted into other forms of energy and gravitational potential energy, the trajectory of the motion is regarded as composed of points, then from the starting point, the starting point has kinetic energy, so there is also an upward velocity, that is, there is a tendency to move upward, then its next point is above the starting point; When an object moves upward, it consumes a certain amount of kinetic energy; But because the kinetic energy is not completely consumed, so this point still has an upward trend, and so on, with the gradual upward, the kinetic energy gradually decreases, and finally decreases to 0, that is, the velocity of the object also becomes 0, because there is no kinetic energy, so the object does not have an upward trend, and can no longer move upward, and at this time the kinetic energy of the object is all converted into gravitational potential energy; In order to release the gravitational potential energy, the object can only move downward, and once the object moves downward, then the height is no longer the highest, so at the highest point, the velocity is 0.

This speed must be stated to be the speed in the vertical direction. If there is velocity in the vertical direction of an object, then the object is either moving upwards or downwards, and it is certainly not at the highest point.

Because he could neither go up (the speed of the upward movement was zero); Running cannot run upwards (the downward velocity is zero), so the velocity is zero, and he has a linear motion and therefore zero velocity.

If the speed of the throw is not 0, the object will continue to fly upwards until the speed is 0.

Because, the kinetic energy of the object is completely converted into potential energy.

This description seems to be imperfect, and in addition to the magnitude of the acceleration, there should be a directional problem. An object that is in upward throwing motion is usually discussed, and it is always accelerated by gravity.

That is to say, the downward acceleration produced by gravity does not change during the movement, and its magnitude can be seen as 10ms. Make a vertical upward throwing motion.

The object has an initial velocity of upward motion, and this muzzle velocity is exactly the opposite direction of gravitational acceleration, so it is decelerating motion, that is, with the increase of motion time, the speed of upward motion gradually decreases, and finally when its upward velocity decreases to 0, because there is no upward velocity of motion, it also reaches its highest point of upward, even if it reaches the highest point, the gravitational force on the object always exists, and the gravitational acceleration always exists, So the object begins to accelerate downward from this point (highest point) in the direction of gravitational acceleration until it hits the ground.

The gravitational force on which an object is subjected during its motion remains constant at all times.

Acceleration is a change in the ratio of the change in velocity at two points to the change in time, the velocity of one point is zero, and it cannot mean that the velocity of another point is also zero.

The velocity of the highest point of the vertical upward throw is zero, but the velocity of all points except the high point is not zero, so the velocity difference is not zero.

The concepts of velocity and acceleration should not be confused.

An acceleration of 10m s 2 is an approximate value.

As we all know, the force experienced by an object due to the attraction of the earth is called gravity. The object of gravity is the center of the earth. The direction of gravity is always straight downwards.

The amount of gravitational force experienced by an object is directly proportional to the mass of the object. This ratio is generally expressed as g, and the value of g may be different in every part of the earth, approximately, usually in simple calculations, take 10n kgWe take its value here as 10 to calculate.

Suppose, the mass of the object is m, then its gravity g=mg. In the process of throwing an object, the object is only affected by gravity, so according to Newton's second law, f = ma, mg = ma can be obtained, so the acceleration a = g = 10m s 2

And the velocity at the highest point is 0, which can be derived according to the formula of acceleration: let the upward direction be positive. Then -2gh=v0 2-vt 2,h=(vt 2-v0 2) 2g

vt 2 is the smallest, and h is the maximum.

And vt 2 is 0 at the minimum, so the above proposition is proved.

Because the direction of acceleration of the object thrown vertically (the direction of gravity) is vertically downward, and the direction of the initial motion of the object is vertically upward (opposite to the direction of acceleration), the object is moving in a deceleration straight line. When an object decelerates to zero, it reaches its highest point. The gravitational force on the object does not disappear at this time, and its acceleration remains at 10m s 2 in the downward direction.

The acceleration is related to the force experienced, and the object thrown upwards is always subjected to gravity, mg, which produces gravitational acceleration g. But the velocity is 0, the end of the up, the beginning of the down. If there is an upward velocity, it will continue to go upwards and will not reach the vertex; If there is a downward velocity, it means that it has been moving downward for a certain period of time, not the highest point.

v=at。

It starts to move upwards, but the object laughs and is subjected to gravity, and the gravity is downward, so the object gradually slows down, decelerates to 0, and then begins to fall downward; It has just started to land, and it is the highest when it has not yet landed, because it has been rising before; At first, the landing becomes no longer the highest, and the landing speed begins to increase, so the maximum speed is 0

In detail: the object can move, so it has kinetic energy, at the starting point, the object has a certain velocity with kinetic energy, the object begins to move upward, due to gravity and resistance, the kinetic energy of the object is consumed, converted into other forms of energy and gravitational potential energy, the trajectory of the movement is regarded as composed of points, then from the starting point, the starting point has kinetic energy, so there is also an upward velocity, that is, there is a tendency to move upward, then its next point is above the starting point; When an object moves upward, it consumes a certain amount of kinetic energy; But because the kinetic energy is not completely consumed, so this point still has an upward trend, and so on, with the gradual upward, the kinetic energy gradually decreases to the sock limb, and finally decreases to 0, that is, the velocity of the object also becomes 0, because there is no kinetic energy, so the object does not have an upward trend, and can no longer move upward, and at this time the kinetic energy of the object is all converted into gravitational potential energy; In order to release the gravitational potential energy, the object can only move downward, and once the object moves downward, then the height is no longer the highest, so at the highest point, the velocity is 0.

The speed of the highest point of vertical upward throwing is zero.

When the object moving vertically upwards reaches the highest point, the vertical minute velocity is zero, and the horizontal direction is not moving, that is, the horizontal velocity is also zero, so the velocity is zero; Since only gravity is applied, according to Newton's second law, acceleration at any moment is equal to the acceleration due to gravity, and the direction is straight downward.

Calculation formula for vertical upward throwing motion:

1.Displacement h=vot-gt2 2.

2.Final velocity vt=vo-gt (g=9..) 8m/s2≈10m/s2)。

3.Useful inference vt' 2-vo 2= -2gh。

4. .Maximum ascent height hn = vo 2 2h (from throwing point).

5.Round-trip time t=2vog (time from throwing back to position).

It can be obtained from the velocity formula and the condition v=0. Note: Contour point V and other general directions are opposite, and the head of the potato hill can be deduced from this formula.

The displacement and unvelocity of the upper throw are easy to calculate. The vertical upward throw motion can be compared to the free fall motion. Generally, g takes 9

8m s32, 10m s2 in specific cases or rough number calculations.

Vertical upward throwing motion nature:

1) Velocity symmetry: When the object passes through the same position during the ascent and descent process, the velocity is equal in magnitude and the direction is opposite.

2) Temporal symmetry: The time it takes for an object to pass through the same height during the ascent and descent is equal.

3) Energy symmetry: the change of gravitational potential energy of the object through the same height during the ascent and descent is equal, and both are mgh.

Since velocity is mentioned, this should be explained in physics;

In physics, whether the same object is in motion or at rest depends on the chosen reference This is the relativity of motion and rest.

In physics, rest represents a relative state, not a simple velocity or acceleration, but if the velocity of an object relative to the reference object is zero, it is the relative reference at rest, and vice versa, it is motion.

Finally, if the reference object referred to by the subject refers to the ground or you who are stationary relative to the ground, at this time, the velocity of the object thrown up is zero relative to the ground, that is, it is stationary relative to the ground.

Because the object thrown vertically is only subject to gravity, it is obtained from Newton's second law: mg=ma

Therefore, the whole process of motion is a linear motion with uniform velocity, that is, the acceleration has always kept the gravitational acceleration unchanged That is, in the vertical upward throwing motion, when the object reaches the highest velocity, the velocity is zero, and the acceleration is still the gravitational acceleration g, so the selection: b

Throw an imitation object obliquely upward, and the object will be thrown obliquely.

Do a uniform deceleration linear motion in the vertical direction, and do a uniform linear rotation in the horizontal direction.

When the object reaches the highest point, the vertical velocity is zero, and the horizontal velocity is not zero, so when the object moves to the highest point, the velocity of the object is not zero, and the direction is along the horizontal direction, so the ACD is wrong to slow the letter and B is correct;

Therefore, b

Select D to decompose the velocity of the ball thrown diagonally upwards into horizontal direction and vertical direction, then the velocity in the vertical direction is less than that of the ball thrown vertically, so A is wrong to rise and the ball is thrown diagonally, and the ball thrown diagonally upwards reaches the highest point first; At the same time, because the ball thrown diagonally upwards has the partial velocity of water as the flat direction, when it reaches the highest point, the velocity is not 0, and the kinetic energy is not fully converted into gravitational potential energy.

It also has the ability to move pure laughter, according to the law of conservation of mechanical energy.

D is right, when the ball thrown vertically reaches the highest point, the kinetic energy is all converted into gravitational potential energy, there is no kinetic energy, B is wrong, C is also wrong,