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Lecture 7. Forces of Inertia
Newton’s Laws are correct only if the coordinate system does not accelerate. The coordinate systems that are at rest or are moving rectilinearly and uniformly are called inertial systems. The inertial systems are connected with so-called “fixed” far stars. The coordinate systems which are moving with acceleration are called noninertial. In an inertial system
Figure 7.1
For a body
Strictly speaking the coordinate that is connected with the Earth is not inertial. In a noninertial system we should add acceleration of body and acceleration of the coordinate system:
The product -
The force caused by an acceleration of the coordinate system is called the force of inertia. Its magnitude is equal to a product of the body’s mass by the coordinate system acceleration. Force of inertia is directed in the opposite direction to acceleration. The force 1) There are no interactions of bodies. 2) It changes as a result of a transition to other coordinate system. 3) It doesn’t obey the Third Newton’s Law. 4) The forces of inertia exist only from the point of view of an observer which is located in the noninertial system. Let us consider an example. A body lies on a cart. Cart starts the motion and moves with acceleration Figure 7.2 Date: 2015-01-12; view: 1338
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