lectures09-page136 - 136 completely trivial point. Masses...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
136 completely trivial point. Masses can be measured against each other without using gravity at all , for example far into space, by comparing their relative accelerations when subject to a standard force, a push. If one object accelerates at half the rate of another when subject to our standard push, we conclude it has twice the mass. Thinking of the mass in this way as a measure of resistance to having velocity changed by an outside force, Newton called it inertia . (Note that this is a bit different from everyday speech, where we think of inertia as being displayed by something that stays at rest. For Newton, steady motion in a straight line is the same as being at rest. That seems perhaps counterintuitive, but that’s because in ordinary life, steady motion in a straight line usually causes some frictional or resistive forces to come into play). 20.13 Mass and Weight To return to the concept of mass, it is really just a measure of the amount of stuff . For a uniform material, such as water, or a uniform solid, the mass is the volume multiplied by the density—
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/08/2012 for the course PHY 322 taught by Professor Daser during the Spring '09 term at SUNY Stony Brook.

Ask a homework question - tutors are online