Which of the following is the MOST appropriate instructional aid for a teacher to INTRODUCE the concept of 'circular motion'?

Option 1 : Blades of a fan 

Circular motion is described as a movement of an object while rotating along a circular path. Circular motion can be either uniform or non-uniform. During uniform circular motion the angular rate of rotation and speed will be constant while during non-uniform motion the rate of rotation keeps changing. 

Circular motion is nothing but an object rotating in the form of a circle as well the object is rotating it forms a shape of a circle.

• Here when the teacher takes the example of the blades of a fan it is a good instructional aid for the teacher to introduce the concept of circular motion.
• The teacher can make the students observe the blades of a fan when the fan is running.
• When the teacher switches on the fan the blades of the fan start rotating in a circular motion rapidly.
• Here the students observe a live example regarding the circular motion of the blades of a fan and learn through experience.

Hence blades of a fan are the most appropriate instructional aid for a teacher to introduce the concept of circular motion. 

• On the other hand door knob, a rope pulley system, and a toy car can't be used as instructional aids to introduce the topic of circular motion because all these objects do not show circular motion when they move from one point to the other.