A piece of wood with a density of 706 kg/m3 is tied with a string to the bottom of a water-filled flask. The wood is completely immersed. Suppose the flask with the wood tied to the bottom is placed on a scale. At some point the string breaks and the wood rises to the surface where it floats.

When the wood is floating, is the reading on the scale greater than, less than, or equal to its previous reading?

less than

greater than

equal to

Choose the best explanation from among the following:

When the block is floating the water level drops, and this reduces the reading on the scale.

The same mass is supported by the scale before and after the string breaks, and therefore the reading on the scale remains the same.

When the block is floating it no longer pulls upward on the flask; therefore, the reading on the scale increases.