Circular Motion Flashcards
Radian definition
the angle subtended at the centre of a circle by an arc of equal length to the radius of the circle
Angular displacement definition
the angle of arc through which the object has moved from its starting position
Subtended definition
the angle between 2 lines that meet at a point is said to be subtended by the 2 lines
Key equation to find angle within a circle
θ = arc length / radius
where θ is the angle in radians
360º is 2π rad
Speed definition
the rate of change of the distance moved by an object, scalar
Velocity definition
an object’s speed in a particular direction, or the rate of change of an object’s displacement, vector
Angular speed definition
the angular displacement per unit
Angular speed equation
angular speed =
angular displacement / time take
ω = ∆θ / ∆t
Angular speed equation for a single revolution
ω = 2π / T
Key equation for speed involving angular speed
speed = angular speed x radius
v = ωr
Newton’s first law (of motion) definition
an object remains at rest or travels at constant velocity unless it is acted on by a resultant force
Centripetal force definition
the resultant force on an object towards the centre of the circle when the object is rotating around that circle at constant speed
Centripetal acceleration definition
the acceleration of an object towards the centre of the circle when the object is rotating at constant speed round that circle
Centripetal acceleration key formulae
a = v² / r
a = rω²
Newton’s second law (of motion) definition
the resultant force on a body is proportional to the rate of change of momentum of the body
