## Episode 223: Preparation for circular motion topic

Teaching Guidance for 16-19

- Level Advanced

There are several demonstrations in this topic which can add a lot to the interest of the subject. It is useful to practise them in advance, to avoid embarrassing failures in front of the students.

A useful source of material is Multimedia Motion II, from Cambridge Science Media. This CD-ROM contains many excellent video clips of motion including that showing an object moving in a horizontal and vertical circle. The position, velocity and acceleration of the object can be analysed.

#### Main aims of this topic

Students will:

- Describe qualitatively motion in a curved path due to a perpendicular force, and understand the centripetal acceleration in the case of uniform motion in a circle
- Express angular displacement in radians
- Recall and use centripetal acceleration
*a*=*v*^{ 2}*r* - Apply the equation
*a*=*F**m*to uniform motion in a circle to derive*F*=*m**v*^{ 2}*r*

#### Prior knowledge

Students should be familiar with the equations of linear motion, and Newton's laws of motion.

#### Where this leads

Circular motion crops up in many different situations, and students will need to be able to apply the equations for centripetal force and acceleration. For example:

- masses orbiting under gravity
- charged particles moving in uniform magnetic fields
- charged particles moving in radial electric fields