Chapter 3, Problem 39A

When you compress a sponge, which quantity changes: mass, inertia, volume, or weight?

To determine

The quantity which changes when a sponge is compressed- mass, inertia, volume, or weight.

Answer to Problem 39A

Only volume changes.

Explanation of Solution

Introduction:

The mass is the quantity of matter in an object while the volume is space taken up by the object.

And, the more the mass of an object, the more will be its inertia. Now, if the given mass of an object is $m$ , then the weight of the object will be,

  $W=mg$

Where, $g=$ acceleration due to gravity

As can be seen from above, only the volume depends on the space covered by the sponge, and all other three quantities, mass, inertia and its weight, depends upon the quantity of matter contained in it.

Conclusion:

Hence, on compression of sponge, only its volume changes.