Measuring Acceleration due to Gravity using a simple Pendulum

Simple Harmonic Motion is very similar to the motion of a bob of a simple pendulum. A simple pendulum is made of a metallic bob suspended by fine string. Using these apparatus the acceleration due to gravity had to be measured. The acceleration due to gravity on earth is 9.81ms-2, therefore every second the particle will increase it’s speed by 9.81ms-1. Although, this may not be the case, due to air resistance.

Acceleration is directly proportional to force and acts towards a fixed position.

## Planning

To derive a value for g, the S.H.M. equation was used:

For calculating ‘g’ the formula had to be rearranged:

T2 = 4π2 l

g

Therefore:

g = 4π2 l

T2

Where: g is the acceleration to gravity; T is the period & l is the length.

Out of the above, the length of the pendulum had to be measured and then the period with that information. Instead of using the formula, a graph could be drawn of length against T2, calculate the gradient, invert it then multiply by 4π…

g = 4π2 l

T2

“”””“””””.. all the weight is at the centre of the bob… - measuring to middle of bob. Keep bob small and dense is important….”””””

5b in analysis.. line of best fit – reason for lack of accuracy – strings got a weight therefore centre of gravity of whole pendulum will not be centre of bob.. Length of pendulum will be shorter than what measuring…”””””””””””