Cirkelrörelse och centripetalkraft: Skillnad mellan sidversioner
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== Teori == | == Teori == | ||
The speed in the formula is squared, so twice the speed needs four times the force. The inverse relationship with the radius of curvature shows that half the radial distance requires twice the force. This force is also sometimes written in terms of the [[angular velocity]] ''ω'' of the object about the center of the circle: | |||
:<math>F = m r \omega^2. \,</math> | |||
Expressed using the period for one revolution of the circle, ''T'', the equation becomes: | |||
:<math>F = m r \frac{4\pi^2}{T^2}.</math><ref>{{cite web|last=Colwell|first=Catharine H.|title=A Derivation of the Formulas for Centripetal Acceleration|url=http://dev.physicslab.org/Document.aspx?doctype=3&filename=CircularMotion_CentripetalAcceleration.xml|work=PhysicsLAB|accessdate=31 July 2011}}</ref> | |||
In particle accelerators, velocity can be very high (close to the speed of light in vacuum) so the same rest mass now exerts greater inertia (relativistic mass) thereby requiring greater force for the same centripetal acceleration, so the equation becomes: | |||
:<math>F = \frac{\gamma m v^2}{r}</math> | |||
{{enwp|centripetal force}} | |||
=== Kommentar === | === Kommentar === | ||
Versionen från 7 oktober 2014 kl. 22.36
Teori
The speed in the formula is squared, so twice the speed needs four times the force. The inverse relationship with the radius of curvature shows that half the radial distance requires twice the force. This force is also sometimes written in terms of the angular velocity ω of the object about the center of the circle:
- [math]\displaystyle{ F = m r \omega^2. \, }[/math]
Expressed using the period for one revolution of the circle, T, the equation becomes:
- [math]\displaystyle{ F = m r \frac{4\pi^2}{T^2}. }[/math]<ref>Mall:Cite web</ref>
In particle accelerators, velocity can be very high (close to the speed of light in vacuum) so the same rest mass now exerts greater inertia (relativistic mass) thereby requiring greater force for the same centripetal acceleration, so the equation becomes:
- [math]\displaystyle{ F = \frac{\gamma m v^2}{r} }[/math]
Kommentar
Boken tar upp dåligt det faktum att:
- Centripetalkraften motsvarar resultaten av de övriga krafterna (exempelvis normalkraft och tyngdkraft)
Filmer att flippa
Frågan är vilka filmer som är bäst och vilka man inte behöver se så noga på
Eller ska alla vara kvar?