Question

Mass of an object in air is 30 kg what will be its mass in water?why?give two precaution while taking reading of water level from a measuring cylinder

Answer 1

Mass of an object will never change even if its medium change. so, the mass of that object will be 30kg in water.

Answer 2

The mass of the object in water will be 30 kg.

• The mass of an object is the amount of matter actually present in it.
• Apart from the relativity theory of Einstein, the mass does not change.
• According to this theory, the mass changes by the following equation,

                       m = $\frac{m_{0}}{\sqrt{1-\frac{v^2}{c^2} } }$

• Otherwise, the mass generally does not change.
• So, the mass of the object in both air and water will be 30  kg.

Only the weight changes as it is the measurement of force, and the acceleration due to gravity is taken into account, which changes from one place to another.