. .
Rigidity Modulus -Static Torsion


Procedure for real lab


The experimental rod is held horizontal and firmly fixed at one end on a suitable frame. The large vertical pulley mounted at other end of the rod. A light  string wound round  the groove of the pulley carries a weight hanger.

A small mirror is fixed at a convenient point on the rod at a distance of about 40cm from one end. The length l of the rod from the clamped end to the mirror is measured. A telescope and scale arrangement is set up at a distance of about 1m from the mirror. The telescope is turned towards the mirror and it is focused at the reflected image of the scale in the mirror. The scale is so adjusted that the reading of the scale in the telescope is near  the centre graduation scale. 

The string is wound once around the pulley in the clockwise direction. The slotted weights are placed on the weight hanger one by one and are removed one by one so as to deform the rod elastically. Starting with the weight of the empty weight hanger, the reading of the scale division coinciding with the horizontal cross wires of the telescope is taken, and again as each weight is added. The weights are removed one by one and the corresponding readings are again taken. The shift in the telescope reading due to the addition of a load is determined. The experiment is repeated by winding the string in the anti-clockwise direction around the groove of the pulley. Hence  is calculated.


Procedure for simulation:


  • Choose material and select the environment.
  • Using the Mirror from fixed end slider, the mirror is fixed on the experimental rod at a suitable distance l (say 25 cm) from the fixed end  of the rod.
  • Using the Scale from mirror slider, the scale and the telescope are placed in front of the mirror at a distance D of 100 to 150 cm. Adjust the Position of  Telescope slider to the same reading as the distance l you chose in the first step. This will bring the image of the scale in the mirror into the center of the viewing field of the telescope.
  • Using the Mass of weight rings slider, the slotted weights are placed on the weight hanger one by one and are removed one by one so as to deform the rod elastically. This procedure is done with the string wound both in clockwise and anti-clockwise direction. (For anti-clockwise, just check the anti-clockwise box at the top of the simulator control panel.)
  • Minimum value of  weight w0 is fixed at 500g.
  • The readings are tabulated and the mean shift S for a mass m is determined.
  •   is calculated.
  • The rigidity modulus is calculated using equation (5) from the Theory page.


Observations and Calculations:






Rigidity modulus (n) =................................Nm-2




Cite this Simulator:

..... .....

Copyright @ 2021 Under the NME ICT initiative of MHRD

 Powered by AmritaVirtual Lab Collaborative Platform [ Ver 00.13. ]