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Model of expansion of the universeA sphere on which surface circles are drawn expands. The distance between the circles grows.In the tool bar it is possible to choose between an open or closed universe. By clicking on button
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Axonometry Axonomet
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Force of attracionThis is the force which two masses M and m attract one another. It is proportional to the mass, and inversely proportional to the square of the distance between two centres.![]() where G is the universal gravitational constant. |
Centre of mass Lets consider a system of bodies of mass ![]() It is possible to broaden the definition to the space by considering also coordinate y and z. |
Vector A vector is a quantity characterized by the fact that has a direction and a magnitude.
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VelocityThe speed v is given by the ratio between the travelled space and the time needed to travel it. Very short intervals will be considered so that the ratio does not vary.![]() The speed is a vector quantity. It is measured in meters per second (m/s). |
Tangential accelerationThere is tangential acceleration when the magnitude of the velocity varies. It has the same direction as the velocity. |
Centripetal accelerationThere is centripetal acceleration when the direction of velocity varies, i.e. when the trajectory is not rectilinear. Its direction is perpendicular to that of the velocity. It is directed towards the centre of curvature of the arc of the trajectory. The magnitude is worth:![]() |
Proportionality
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