Grandfather Clocks Are Designed So They Can Be Adjusted by Moving

Grandfather clocks are designed so they can be adjusted by moving the bob at the bottom of the pendulum up or down.Suppose you have a grandfather clock at home that runs slow.Which of the following adjustments of the bob would make it more accurate? (There could be more than one correct choice.)

A) Raise the bob.
B) Lower the bob.
C) Add more mass to the bob.
D) Remove some mass from the bob.
E) Increase the amplitude of swing by a small amount.