A pendulum has a period of 1.8 s.

Question

a) Its mass is doubled. What is its period now?

b) Its length is doubled. What is its period now?

The original pendulum is taken to a planet where g = 16 m/s2.
c) What is its period on that planet?

Answer 1

You should be able to figure these out yourself using the formula for the Period:

P = 2 pi*sqrt(L/g)

Note that it does not depend upon the mass of the pendulum.

Answer 2

really?? but how would i find L?

Answer 3

If you double L (the length), P increases by a factor sqrt2 = 1.414, no matter what L is.

Answer 4

(a) time period is independent of mass. so time period of pendulum remains same.
(b)
let initial time period be t1 when length is l and t2 be time period after double of length,i,then
t1=sqrt(l/g)....(1)
t2=sqrt(2l/g)
=root 2xsqrt(l/g)....(2)
from 1 and 2,
t2=root 2 times t1
where t1=1.8 s

(c)ti/t2=sqrt(g'/g)
where g=9.8m/s,ti=1.8s and g'=16m/s
solve n u will get answer