Circular Motion Flashcards
Define a radian
The angle subtended at the centre of a circle by an arc equal in length to the radius
What is 1 rad equal to in degrees?
57.3 degrees
360 degrees is equal to how many radian
2π rad
Define frequency
Number of oscillations per second
Define period,T
Time taken to complete one complete oscillation/revolution
State the relationship between f and T
f=1/T
What is angular velocity?
The angle swept out by the radius in unit time
ω=Θ/t
State the equation for angular velocity of a full circle
ω=2π/T =2πf
How to convert from rpm to rad/s ?
multiply with pi and then divide by 60
Explain how a particle, travelling in a circle at constant speed, can be accelerating
Acceleration is a vector quantity.
There is a constant speed (magnitude) but there is a constant change in direction because the particle is travelling in a circle. Thus, the particle is accelarating
Centripetal acceleration equations
a=v²/r and a=ω²r
A body cannot move in a circle at constant speed without having what acting upon it?
Resultant force-always directed towards the middle
State the relationship between centripetal force and the velocity
Directly proportional
State the equations associated with centripetal acceleration
F=mv²/r and F=mω²r
Why does the speed of an object not change in circular motion?
The net force is directly perpendicular to the direction of motion.
So there is no work done by the force and no change is speed.
W=fxcosΘ and cos90=0 so W=0J
