Circular Motion

Centripetal Force

Measuring angles

Resultant force that causes an object to move in a circular motion.

Netwon's First Lay states that:

"An object continues to move in a straight line unless a resultant force acts on it"

So to make something move in a circle, we need a force

force_centripetal_equation

No work is done

The object is moving in a direction along a tangent to the circle. The force is always to 90 degrees to this, towards the centre. So, there is no movement in the direction of the force,

Measuring angles

360 degrees = 2pi radians

1 radian ~ 57 degress

Time Period and Frequency

Time to complete 1 rotation

Frequency = Number of Rotations / Time taken

Measured in Hertz (Hz)

Angular Speed

Angle that is turned through in a given time

Angle turned through (rad) / time taken (s)

Symbol = ω

Centripetal Acceleration

ω = 2pi/T

ω = 2xpixf

v=r x ω

Velocity is changing --> Acceleration is occuring

a = (v^2)/r

a = rω^2

F=mv^2 / r

F=mrω^2