The change in kinetic and mechanical energy when the spaceship lands

The reaction force of the jet gas slows it down, so the kinetic energy decreases.

Due to the decrease in altitude during the landing process, the gravitational potential energy decreases, and because the kinetic energy also decreases, the mechanical energy decreases from the mechanical energy = kinetic energy + potential energy, and the explanation for this is because the spacecraft emits high-temperature gas to do work externally, so that its own mechanical energy is reduced.

Converts gravitational potential energy into kinetic energy.

Since the final velocity of the rocket is much smaller than before (approaching zero) in order to land safely, and the mass of the rocket remains the same, according to e=1 2mv 2, the kinetic energy can be seen.

Whereas, mechanical energy is equal to the sum of gravitational potential energy and kinetic energy, the kinetic energy decreases, and the gravitational potential energy decreases (gravity does positive work), so the mechanical energy also decreases. It can also be considered from another point of view, the mechanical energy of the rocket in mid-air is e1, and the landing is e2, and e1-e2 = w (w is the work done by the internal force, the title means "high temperature", that is, the internal energy increases), because w is positive, so e1 > e2, so the mechanical energy is reduced.

Kinetic energy = 1 2mv'2 Gravitational potential energy = mgh mechanical energy = kinetic energy + potential energy So the kinetic energy does not change The gravitational potential energy increases and the mechanical energy becomes larger.

1. When an airplane accelerates its ascent, both kinetic energy and mechanical energy become larger.

2. Kinetic energy = 1 2mv'2. Gravitational potential energy = mgh, mechanical energy = kinetic energy + potential energy; So the kinetic energy increases, the gravitational potential energy increases, and the mechanical energy increases.

3. Kinetic energy is the energy that an object has due to its mechanical motion.

4. Mechanical energy is the sum of kinetic energy and potential energy, and the potential energy here is divided into gravitational potential energy and elastic potential energy. We refer to kinetic energy, gravitational potential energy, and elastic potential energy collectively as mechanical energy. It is mass and velocity that determine kinetic energy; It is the mass and height that determine the gravitational potential energy; The elastic potential energy is determined by the stiffness coefficient and the deformation.

Mechanical energy is simply the sum of kinetic energy and potential energy. Mechanical energy is a physical quantity that represents the state and height of an object. There is a conversion between the kinetic energy and the potential energy of an object.

In the process where only kinetic energy and potential energy are converted into each other, the total amount of mechanical energy remains the same, i.e., mechanical energy is conserved.

Deficit 1) During the acceleration of the spacecraft in Qizheng, its speed increases and its kinetic energy increases; Its height increases, quietly singing the gravitational potential energy.

become larger; So mechanical energy.

Enlarge; 2) the astronaut, although the position has changed, the mass does not change;

So the answer is: enlarge; No change

The reaction force of the jet gas slows it down, so the kinetic energy decreases.

Due to the decrease in altitude during the landing process, the gravitational potential energy auspicious impulse decreases, and because the kinetic energy also decreases, the mechanical energy decreases from the mechanical energy = kinetic energy + potential energy.

When the spacecraft falls, gravity does positive work to increase the speed of the spacecraft, increase the kinetic energy, and decrease the potential energy; Due to the existence of air hail transport resistance in the process of falling, the spacecraft has to overcome the resistance and do work to reduce the mechanical energy, so in general, the gravitational grinding potential energy of the spacecraft decreases, the kinetic energy blindly increases, and the total mechanical energy decreases.

The meteors we see are caused by the work of an asteroid or meteorite that overcomes air resistance during its fall and converts mechanical energy into internal energy.

Kinetic energy: ek = 1 2mv

Gravitational potential energy: ep=mgh

Because of the airdrop of supplies. So the mass is rotten m decreased.

So all decrease. Select B

Hope mine is helpful to you.

Happy talking!

Stretch the trampoline to the lowest point as 0 potential surface:

Ascending process: first from the trampoline to the original unstretched form, in this process the elastic potential energy of the trampoline is all converted into the child's gravitational potential energy and kinetic energy, the next moment, the child leaves the trampoline and continues to rise to the highest point, in this process the child's kinetic energy is all converted into gravitational potential energy.

Descent process: It is just the opposite of the ascent process, from the highest point to the contact with the trampoline, part of the gravitational potential energy in this process is converted into kinetic energy, and after contact, the trampoline continues to be stretched downward, and the gravitational potential energy and kinetic energy are all converted into elastic potential energy.

The above is the general energy conversion process, but to ask the specific kinetic energy maximum point needs to be detailed analysis, after the falling process and trampoline contact, the child is subjected to downward gravity and upward elasticity in the vertical direction, and the gravity remains unchanged, and the elastic force is increasing. Therefore, for a period of time after touching the trampoline (when gravity is greater than elastic force), the child's acceleration is still downward, and the acceleration movement with reduced acceleration is still continued. Until the acceleration decreases to zero, the velocity reaches the maximum, which is the time when the kinetic energy of the king is the largest, and the next moment the elastic force is greater than the gravity and the acceleration of the wide boy is reversed, and the child does the deceleration movement with increased acceleration.

So the maximum kinetic energy is when gravity is equal to elastic force!!

Stretch the trampoline to the lowest point as 0 potential surface:

First by the trampoline to the original unstretched form, in this process the elastic potential energy of the trampoline is all converted into the child's gravitational potential energy and kinetic energy, the next moment, Xiao guess this round of friends leave the trampoline and continue to rise to the highest point, this process of the child's kinetic energy is all converted into gravitational potential energy.

During the acceleration of the manned spacecraft, the speed of the spacecraft increases, so the kinetic energy of the spacecraft increases When returning through the atmosphere, the spacecraft overcomes friction and converts part of the mechanical energy into internal energy, so that its internal energy increases and the temperature rises

When the basketball falls from the air and hits the ground and the elastic deformation occurs, the height decreases and the velocity increases, and then the velocity decreases when the ball hits the ground, and the degree of elastic deformation increases, so in this process, the transformation of the mechanical energy of the ball undergoes a transformation from gravitational potential energy to kinetic energy and then to elastic potential energy

So the answer is: enlarge; Inside; Geopotential; Move; Elastic potential

When the spacecraft lifts off, the speed gradually increases, and the kinetic energy increases; As the height becomes larger, the gravitational potential energy increases, and therefore the mechanical energy increases

Therefore, choose D