Spinning Science | Kannada
Channel: Arvind Gupta
Date: 2016-06-29

So we will place this piece on the spool and move the piece forward. Notice that the front end of the piece and the spool is at the same point as the piece. So now when we move the wheel we see piece starts moving forward than the wheel. 

Now when we make the measurement we can see that when the wheel has moved equal to length of the piece the piece has moved two times. 

It is very counter intuitive as if the passenger on the car has moved further than the car. This is exactly how in olden time people used to move large pieces of stone taking the advantage of this fact.

This happens because the piece on top is sitting on the outer surface of the wheel and hence gets two different motions. It goes twice because it moves as much as the wheel moves forward and also moves forward because of spin of the wheel. So the speed of the piece and distance covered by the piece is two times that of wheel.

Yes we can. Now we can see that piece is sitting on the outer circle while the wheel is spinning
on the inner circle. So in one turn of wheel, wheel moves proportional to inner diameter.
But piece moves as much as the wheel and extra proportional to outer diameter.

Now the inner diameter is 6cm half the outer 12cm. So the piece moves three times the wheel.
Formula 1 + Diameter on which the piece moves/Diameter in which the wheel spins.

1 + 12/6 = 3. In the former case Diameter of wheel on which it spins and Diameter on which piece moves is same so wheel moves

1 + 12/12 = 2. And hence when we keep the piece very close to center of wheel the piece will go as much as the wheel. 1 + 0/diameter of wheel = 1.

This work is supported by IUCAA (www.iucaa.in) and TATA Trust (www.tata.com/aboutus/sub_index/Tata-trusts)

Credits:,Ashok Rupner, Manish Jain, Pradnya Pujari, Shivaji Mane, Jyoti Hiremath, Arvind Gupta, Vidula Mhaiskar

Dubbed in Kannada by PK Nanawaty TATA Trust: Education is one of the key focus areas for Tata Trusts, aiming towards enabling access of quality education to the underprivileged population in India. To facilitate quality in teaching and learning of Science education through workshops, capacity building and resource creation, Tata Trusts have been supporting Muktangan Vigyan Shodhika (MVS), IUCAA's Children’s Science Centre, since inception. To know more about other initiatives of Tata Trusts, please visit www.tatatrusts.org