An aluminium block is hung on a spring balance and weighs 12 N when fully immersed in a glass of water. What is its weight in air?
(The density of aluminium is 
and that of water is 
).
Before immersing the aluminium block in water, the glass of water weighed 2 kg on a weighing scale. What is the measurement shown by the scale when the block is immersed in the water? (The block does not touch the bottom of the glass!)
