In the process of elevator ascending, the upward gravity (including the gravity of the elevator itself and the gravity exerted by people inside the elevator) is greater than the downward gravity (including the gravity of people carried by the elevator and the gravity of the elevator itself), so the net force on the elevator is upward, and the elevator will move upward at a certain acceleration. This acceleration depends on the net force on the elevator and the quality of the elevator itself.
When the elevator rises at a constant speed, the upward gravity on the elevator is equal to the downward gravity, and there is no net force between them, so the elevator keeps moving in a straight line at a constant speed.
It should be noted that when the elevator rises, the gravity felt by human body will also change, increasing with the increase of acceleration and decreasing with the decrease of deceleration. When the elevator reaches a certain speed, the human body will feel the same gravity as the gravity of the earth. At this time, the human body will not feel the motion state of the elevator.
Application field of Newton's second law
Some dynamic problems can be solved by applying Newton's second law of motion. There are mainly two kinds of problems: the first kind of problems is that the mass and motion state of a particle are known, and the position of the particle at any time is known, that is, the equation of motion or the expression of velocity or acceleration, to find the force acting on an object, generally taking the second derivative of the known equation of motion or the first derivative of the velocity equation to find the acceleration, and then finding the unknown force according to Newton's second theorem;
In the second kind of problem, the mass of a particle and the force acting on it are known, and the motion state of the particle, that is, the motion equation, velocity expression or acceleration expression, is obtained. Usually, Newton's second law of motion lists equations and finds an acceleration expression of an object. The velocity expression is solved by a definite integral with acceleration and initial conditions, and the motion equation is solved by a definite integral with velocity expression and initial conditions. There are four main methods to solve the problem: critical condition method, orthogonal decomposition method, synthesis method and programmed method. ?
Using Newton's second law and the same linear vector synthesis method, according to the physical characteristics of the ideal "parallel guide rail model" and based on the law of electromagnetic induction, various situations of the capacitive load parallel guide rail model in electromagnetic induction can be calculated, and the mathematical expression of the movement of the metal guide bar in various situations can be calculated. The result is consistent with the reality.
Animation is a kind of film and television art that makes the picture move, that is, the moving picture. Newton's second law of motion plays an important role in animation art and is an indispensable research object in animation.