# Variation of Acceleration due to Gravity on Earth's Surface

**Pages:**3 (251 words)

**Published:**February 25, 2014

VARIATION OF ACCELERATION DUE TO GRAVITY ON

EARTH’S

SURFACE & TO FIND ITS VALUE AT A PLACE

Name of student: ……………………………………………………………………… Class:………………………………

Section:…………………………..

Roll:…………………………………

School: …………………………………………………………………………………………..

1

Introduction.

Acceleration due to gravity varies from place to place on the earth’s surface. This is due to the fact that the radius of earth varies from place to place as earth is not a perfect sphere.

g

GM

R2

Theory.

The acceleration due to gravity at a place can be calculated by knowing the approximate values of time period of oscillation and length of pendulum.

l

g

T 2

Where T= time period, l effective length of pendulum, g=acceleration due to gravity at the place of observation.

l

4 2l

T 4

or g 2 .

g

T

2

2

Hence, to find the acceleration due to gravity at a place on earth’s surface, we need to know the effective length of pendulum & time period.

Materials required:

All you have to do is use the materials easily available at home. (i)

(ii)

(iii)

(iv)

Marble ( acting as the bob)

Threads ( acting as the pendulum’s length)

Ruler ( for measuring approximate length of pendulum)

Mobile handset ( to be used as stop watch)

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DATA

No. of

obs

Radius of

bob (r)

Length of

thread(l’)

Effective

Time period

length(l=l’+r) of 20

oscillations

Mean l

Mean T

1

2

3

Calculation: The calculated value of g at the place of observation is

g

4 2l

= …………….ms-2

T2

Conclusion: The observed value of acceleration due to gravity at …………………………………………(name of locality/city) is ……………………………..

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