Сформулируйте вопросы на английском языке и дайте ответы на них. Какие типы взаимодействия существуют в природе? Опишите их природу. Укажите их радиус действия.
What kinds of interactions exist in nature? Describe their nature. Define their radius of action.
There are four types of interaction: 1) gravitational, 2) electromagnetic, 3) strong, 4) weak. Gravitational interaction exists between objects with mass, electromagnetic interaction occurs when bodies are charged. These two interactions have very wide radius of action. Strong interaction occurs into the atom, weak – in the molecule.
Сформулируйте вопросы на английском языке и дайте ответы на них. Какое тело называется свободным? Что такое поле в физике? Что такое сила? Куда приложена сила тяжести, действующая на тело, и как она направлена?
Which body is called free? What is the field in physics? What is the force? Where lays the point of acting of gravity forces and where it is directed?
Body can be called free if there are no any forces which are acting on it.
Field is the special form of matter via which bodies interact with each other (gravitational field, electromagnetic field).
Point of acting of gravity force is called center of mass of that body. The force is directed to the center of Earth.
Примечание: нарисовать тело и показать силу тяжести.
Сформулируйте вопросы на английском языке и дайте ответы на них. Какие силы в механике вы знаете? Сформулируйте законы Ньютона. Что такое инерциальная система отсчета?
What forces in mechanics do you know? Formulate the laws of Newton. What is inertial reference system?
Gravitational force, weight of body, elastic force, friction.
Newton’s laws:
First law: When viewed in an inertial reference frame, an object either is at rest or moves at a constant velocity, unless acted upon by an external force.
Second law: The acceleration of a body is directly proportional to, and in the same direction as, the net force acting on the body, and inversely proportional to its mass. Thus, F = ma, where F is the net force acting on the object, m is the mass of the object and a is the acceleration of the object. Force and acceleration are both vectors (as denoted by the bold type). This means that they have both a magnitude (size) and a direction relative to some reference frame.
Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body.
Inertial reference system is a system where body moves with constant velocity and straight lined trajectory or at rest, if there are no any forces acting on that body or action of these forces are compensated.
Сформулируйте вопросы на английском языке и дайте ответы на них. Чему равна гравитационная сила? Сформулируйте закон всемирного тяготения. Что такое инертная и гравитационная масса?
Formulate the law of universal gravitation.
Newton’s law of universal gravitation states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
where F – is the force between the masses, G – is the gravitational constant, m1 – is the first mass, m2 – is the second mass, r – is the distance between the centres of the masses.
What is the inertial and gravitational mass?
Inertial mass is a measure of an object’s resistance to changing its state of motion when a force is applied. An object with small inertial mass will accelerate more than an object with large inertial mass when acted upon by the same force.
Gravitational mass is the physical property of an object that causes it to interact with other objects through the gravitational force. According to the equivalence principle, gravitational mass is equivalent to inertial mass.