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class 19 CIRCULAR MOTION - Mr. Gopie...
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Mr R Gopie Circular Motion PHYSICS
Transcript of class 19 CIRCULAR MOTION - Mr. Gopie...
Mr R Gopie Circular Motion
PHYSICS
Mr R Gopie PHYSICS
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CIRCULAR MOTION
Consider a body (of mass, m) moving at a constant sped (v) in a circular path (of radius, r).
In position (1) the velocity v1 (of magnitude v) is directed along a tangent at that point (as shown)
Diag. 35
In position (2) the velocity v2 (of magnitude v) is directed along another tangent, at that point (as shown) since the direction of the velocity changes and velocity is a vector quantity then the velocity changes (at each point) along the circumference. However, a change in velocity is by definition, an acceleration and therefore the body undergoes acceleration as it moves along the circular path at constant speed.
By newton’s second law of motion, if the body is accelerating then it must be experiencing a resultant, or unbalances force. The resultant force is called a centripetal force and the acceleration associated with it is called a centripetal acceleration. Both are vector quantities and are directed towards the centre of the circular path (along a radius at a given point on the circumference). For anybody to move in a circular path with uniform speed it must be provided with a centripetal force which must be a resultant (i.e. unbalanced) force acting on the body. Such a force is either a single force or the resultant of a system (or set) of forces acting on the body.
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Examples Include:
Body Moving In Uniform Circular Motion Source of Centripetal Force Planet Orbiting the sun Gravitational force of attraction exerted on the
planet by the sun Object held to one end of a string and whirled around
The tension in the string
A vehicle negotiating a corner on a flat road Lateral function between the wheels and the road.
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Tutorial
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June 2003 paper 2 #5
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Mr R Gopie PHYSICS
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