# Bifilar Suspension - the technique will be applied to find the mass moment of inertia of a regular cross-section steel beam about its centre of gravity.

Suspension bridges :

AIM OF THE EXPERIMENT:

To find the relation between the time take and the distance in a suspension bridge where the distance increases as (6cm, 8cm, 10cm, 12cm, 14cm, 16cm.)

INTRODUCTION:

The Bifilar Suspension is a technique that could be applied to objects of different shapes, but capable to be suspended by two parallel equal-length cables, in order to evaluate its mass moment of inertia I about any point within the body.

In this experiment, the technique will be applied to find the mass moment of inertia of a regular cross-section steel beam about its centre of gravity.

This is done by suspending two parallel cords of equal length through the object examined.

The system oscillates because any rotation of the rod away from its equilibrium position moves the strings away from the vertical, which lifts the rod upwards and increases its potential energy.

VARIABLES:

Independent variables: The distance from the middle point of both parallely arranged scles i.e. 50cm and 25cm. The distance starts from 6cm, 8cm, 10cm, 12cm, 14cm and 16cm on both th sides. The initial distance was chosen to be 6cm because the measures below that did not favour the setup as the oscillations were not possible.

Dependent variables: The time taken for 10 oscillations by the scale which was measured using a digital stop watch.

Controlled variables: The controlled variables are as follows:

- The mean position of the scale placed on the top: 50cm
- The mean position of the scale placed below: 25cm
- Number of strings used: 2 strings
- Length of each string: 16.5cm.
- Distance between the two ends of the scale placed above: 90cm