the diagram above shows a uniform metre rule, X Y which is balance horizontally at the 90cm mark, when a mass of 0.4kg is suspended from Y. what is the mass of the metre rule​

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

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answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg

can somebody give me the answer so i can graduate