5.2 Circular Motion Flashcards
what is one radian defined as?
one radian is defined as the angle subtended at the centre of a circle when the arc length is equal in length to the radius of the circle
what is 2π radians equal to?
360° (a full circle)
define frequency
no. of complete revolutions per second
define period
the time period is the time taken in seconds for one complete circular path
what is angular velocity ω?
the rate of angular rotation measured in radians per second, rad s^-1
what is the angular velocity formula? (ω)
ω = 2π / T or ω = 2πf
what is the formula for constant linear speed in a circle?
v = ωr
how do you get to the constant linear speed in a circle equation?
V = d / t
V = 2πr / t
subbing in ω = 2π / T gives you…
v = ωr
are objects travelling in circles accelerating?
yes since their velocity is changing because their direction is changing (actual speed in a circle is constant) and acceleration is defined as the rate of change of velocity
what is centripetal acceleration?
the acceleration of an object moving in a circle and it is always defined directed towards the centre of the circle
what is a key point about circular motion in terms of acceleration and velocity?
there is no acceleration parallel to the direction of motion, velocity remains perpendicular to the direction of the force/acceleration
what is the formula for centripetal acceleration?
a = v^2 / r a = ω^2 x r (since v = ωr) where a = centripetal acceleration v = linear velocity ω = angular velocity r = radius
what is the name of the force that keeps something moving in a circle?
centripetal force
what is the definition of centripetal force?
the centripetal force is the resultant force on an object acting towards the centre of the circle, causing it to move in a circular path
in what direction does the centripetal force and acceleration act?
radially inwards towards the centre of the circle