Question

You have a bag of cotton and an iron bar, each indicating a mass of 100 kg when measured on a weighing machine. In reality, one is heavier than other. Can you say which one is heavier and why?

Answer 1

100kg cotton weighs more than 100kg iron. Air also causes buoyancy. And buoyancy is more on cotton if it measures 100kg on measuring device it would be more than 100 in actual.

Answer 2

$\huge\mathfrak{{answer}}$

The bag of cotton is heavier than the bar of iron. The cotton bag has a larger air thrust than the iron bar. The weighing machine therefore indicates a smaller cotton bag weight than its actual weight.