2 particles, each of mass 'm' and speed 'v', travel in opposite directions along parallel lines separated by distance 'd'. Show that vector angular momentum of the 2-particle system is the same whatever be the point about which the angular momentum is taken.
2007-12-28 15:28:19 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Physics
They're at a 180 degree angle from each other at some distance (d), along the x axis, with but parallel to each other along the (z) axis. Momentum is traveling in the negative and posive directions along the (x) axis. If the whole thing is one system, then momentum is conserved.
I'm lost. Forget about it.
2007-12-28 15:35:20 · answer #1 · answered by Anonymous · 0⤊ 0⤋
a vector from a point to the particles is r1 and r2 and to the center of mass of the system is r. L1 and L2 is the vector from the center of mass to each particle
r1=r+L1 and r2=r+L2
so the angular momentum
= r1 X mv1+r2 X mv2
=(r+L1) X mv1 +(r+L2)X mv2
=r X mv1+r X mv2 + L1 Xmv1 + L2 Xmv2
but r X mv1+r X mv2 =0 because mv1=-mv2 so the answer does not depend on r that is the choice of the distance or direction of the point from the center of mass of the system
2007-12-29 00:10:42 · answer #2 · answered by meg 7 · 0⤊ 0⤋