A mass on a string of unknown length oscillates as a pendulum with a period of 6 s. What is the period in the following situations? (Parts (a) to (d) are independent questions, each referring to the initial situation.)
(a) The mass is doubled.
s
(b) The string length is doubled.
s
(c) The string length is halved.
s
(d) The amplitude is doubled.
s