http://www.ck12.org Chapter 6. Centripetal Forces
- If a particle travels a distance 2πrin an amount of timeT , then its speed is distance over time or 2 πr/T.
- An object moving in a circle has an instantaneous velocity vectortangentialto the circle of its path. The force
and acceleration vectors point to the center of the circle. - Net force and accelerationalwayshave the same direction.
- Centripetal acceleration is just the acceleration provided by centripetal forces.
- Any force can be a centripetal force. Centripetal force is the umbrella term given to any force that is acting
perpendicular to the motion of an object and thus causing it to go in a circle. - When undergoing centripetal motion you might ’feels’ an outward pull, however this is not a true force, but
merely the objects inertia. Remember, Newton’s first law maintains that the natural state of an object is to go
in a straight line at constant speed. Thus, when you make a right turn in your car and the basketball in the
back seat flies to the left, that is because the car is moving right and the basketball is maintaining it’s position
and thus from your point of view moves to the left. Your point of view in this case is different from reality
because you are in a rotating reference frame. - The Geosynchronous orbit is the orbit where a satellite completes one orbit of the Earth every 24 hours, staying
above the same spot (longitude) on Earth. This is a very important orbit for spy satellites and TV satellites
among others. You force the speed of the satellite to be a value such that the satellite makes one rotation every
24 hours.
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