Question

a pendulum whose length is 25 cm has time period 1.2 second . find the time period for another pendulum of length 36 cm.

Answer 1

here find the ratio of t^2/l. it is in this case 36/625 where t is 1.2 and l is 25.
then multiply it with 36 to get the value of t2^2 and then find it's square root to get the answer.
the answer is 1.44 second.