What is angular displacement
angle through which an object turns about the centre of a circle
What is radian?
angle subtended at the centre of a circle by an arc equal in length to the radius of the circle
What is angular velocity?
rate of change of angular displacement
What is centripetal force?
a resultant force acting on a rotating object which moves in uniform circular motion, centripetal force always points towards centre of rotation
What is uniform circular motion?
motion of an object moving in a circular path at constant speed
Why is there a resultant force acting on a ball moving at constant speed in a circular path?
- although the speed is constant, the direction of the ball is always changing, hence its velocity is changing, thus the ball accelerates
- By Netwon’s second law, a resultant force must have acted on it
Why does centripetal force point towards the centre of rotation?
- since the object moves with constant tangential speed, the tangential force is 0
- resultant force must act perpendicular to the path such that the force only changes direction but not tangential speed
What is frequency?
an object in circular motion is the number of revolutions made by the object per unit time
What is period?
the time taken for the object to make one complete revolution
