Circular motion Part 1

Define angular speed, its equation and units

The angle turned through per second, $\omega=\frac{\theta}{t}$ , units = $rads^{-1}$

State all 3 equations for linear speed (that do not include angular speed)

$$v=\frac{d}{t}=\frac{2\pi r}{T}=2\pi rf$$

State the equation that can be derived from $\omega=2\pi f$

$$\omega=\frac{2\pi}{T}$$

Due to Newton’s First Law, why is a constant force needed for an object to follow a circular path

• In circular motion, the objects direction is constantly changing, velocity is a vector so the velocity is constantly changing, which means the object must be accelerating towards the centre of the circle and according to Newtons 1st Law a resultant force is required if the object is accelerating.

When an object is following a circular path, state the force acting and in which direction

The force acting is the centripetal force, which acts towards the centre of the circle

State 3 objects moving in circular motion and their centripetal force

• Satellite orbiting earth → Gravity

• Vehicles on circular path/bend → Friction between tires ad road

• Hammer throw → Tension is steel wire