escapements gears lever weights chain bob pendulum- Old mechanical 'grandfather clocks' (left) have a pendulum that is driven by falling weights. In theory, it takes a week for the weight to reach the bottom of it's run, and then you have to pull it up again. Someone had a clock that, when wound up on Sunday, would stop sometime in the middle of the night between Thursday and Friday. The stoppage was accompanied by the sound of the weights hitting the side of the case. When this happened, the distance between the centre of mass of the weight and the suspension point was 0.99m. Use the concepts of damped driven oscillation and coupled oscillations to explain why the clock stops at the time it does. (20) This image shows the internals of a typical grandfather clock.