Question

why we assume that the mass attached to simple pendulum is negligible?

Answer 1

it isn't negligible..only the mass of string is assumed negligible..

Answer 2

why is it?

Answer 3

if you study the differential equation (not the newton's law approximate derivation)needed to derive the time period,u will see that it require all mass swinging to be at the centre of blob...

Answer 4

but why we neglect mass of string?

Answer 5

@Mamoona_akbar You are confusing two different things:

- mass is negligible
- mass cancels out from equation (does not appear in final result)

Answer 6

because otherwise tension will not be uniform throughout the string..

Answer 7

if string had some mass then the moment of inertia of string mass system about the point of hanging will change and so,also will change, the expression for time period..

Answer 8

In practice even though present ,the mass of string is comparatively very small and the string is also much closer to the point of hanging,so it will not really change the moment of inertia to any significant extent..so we just neglect that term..

Answer 9

We assume that mass of string is negligible to have a simpler model.

Physics is about understanding fundamental laws of nature. You usually start studying problems with as few degrees of freedom as possible. Choosing a string with mass would make the problem too complicated.

Answer 10

but sir..we learn physics to understand these complications..i just want to know either these complications matter or not..
if not then why..?