Practical Mathematics K11Big Ben is the nickname for the Great Bell of the clock at the north end of the Palace of Westminster in London, United Kingdom.

A pile of old coins helps to keep the clock mechanism accurate. The pennies are stacked on the pendulum of the clock and have acted as weights. Adding or taking away coins effects the pendulum’s center of mass and the rate at which it swings. A single penny will change the clock’s speed by two fifths of one second per day.

How does the weekly time change if we add 5 pennies to the pendulum?