If both the length and mass of a simple pendulum are increased, the frequency of the pendulum will decrease.
The frequency of a simple pendulum is inversely proportional to the square root of its effective length. The effective length is the distance from the pivot point to the center of mass of the pendulum bob. When the length of the pendulum is increased, the effective length also increases, which leads to a decrease in frequency.
Additionally, the frequency of a simple pendulum is independent of its mass. Changing the mass of the pendulum bob does not directly affect the frequency. However, altering the mass can have an indirect effect on the pendulum's behavior due to changes in the pendulum's period, which is the reciprocal of frequency. The period of a pendulum is directly proportional to the square root of its effective length. Therefore, increasing the mass of the pendulum bob while keeping the length constant will increase the period and, consequently, decrease the frequency.
In summary, increasing both the length and mass of a simple pendulum will result in a decrease in its frequency.