A pendulum is a mass connected to a light string or rod which is connected to the ceiling. The period is the amount of time it takes the bob (as the mass is called) to swing from one side to the other and back. It is given by
where T is in s, l is the length of the string or rod (in m), and g is the acceleration due to gravity (m/s2). (See Figure.)
If the length of the string of a pendulum is increased by a factor of 4, how does the period change?