Question

Bandish and Parag, on a trek to Sandakpu, halted at a tea house in Tumbling. The picture shows the entrance door of the tea house. They saw the tumbrel filled with water hanging from top rigid support passing through the door. On enquiring about the tumbrel, the owner of the tea house, he said that it acts as a pullback (door closure) after opening and releasing the door.

1. Explain how the tumbrel helps to close the door on its own.
2. Name the principle involved.

Answer 1

1. When the door is opened, the tumbrel is lifted. When the door is released, the tumbrel’s weight pulls it down and turns the door back towards its closed position.
2. The principle of moments is involved: the turning effect produced by the weight of the tumbrel makes the door rotate and close.