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Reduced mass

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For typical applications in nuclear physics, where one particle's mass is much larger than the other the reduced mass can be approximated as the smaller mass of the system. The limit of the reduced mass formula as one mass goes to infinity is the smaller mass, thus this approximation is used to ease
1930: 3085: 1042: 2304: 1024: 359: 1610:{\displaystyle \mathbf {a} _{\rm {rel}}=\mathbf {a} _{1}-\mathbf {a} _{2}={\frac {d^{2}\mathbf {x} _{1}}{dt^{2}}}-{\frac {d^{2}\mathbf {x} _{2}}{dt^{2}}}={\frac {d^{2}}{dt^{2}}}(\mathbf {x} _{1}-\mathbf {x} _{2})={\frac {d^{2}\mathbf {x} _{\rm {rel}}}{dt^{2}}}} 3357: 3554: 2831: 3362:
we find that the position of the first body with respect to the second is governed by the same differential equation as the position of a body with the reduced mass orbiting a body with a mass equal to the sum of the two masses, because
1768: 2387: 1252:{\displaystyle \mathbf {a} _{\rm {rel}}:=\mathbf {a} _{1}-\mathbf {a} _{2}=\left(1+{\frac {m_{1}}{m_{2}}}\right)\mathbf {a} _{1}={\frac {m_{2}+m_{1}}{m_{1}m_{2}}}m_{1}\mathbf {a} _{1}={\frac {\mathbf {F} _{12}}{\mu }}} 499: 3186: 3613: 1724:. Thus we have reduced our problem to a single degree of freedom, and we can conclude that particle 1 moves with respect to the position of particle 2 as a single particle of mass equal to the reduced mass, 2160: 2072: 2148: 901: 614: 146: 833: 773: 2467: 1665: 890: 2750: 2677: 426: 3436: 3221: 1702: 1334: 1297: 3472:. They orbit each other about a common centre of mass, a two body problem. To analyze the motion of the electron, a one-body problem, the reduced mass replaces the electron mass 1964: 690: 657: 2819: 3478: 549: 2602: 2575: 2548: 2521: 1991: 1742: 1722: 97: 69: 2773: 2012: 1925:{\displaystyle {\mathcal {L}}={1 \over 2}m_{1}\mathbf {\dot {r}} _{1}^{2}+{1 \over 2}m_{2}\mathbf {\dot {r}} _{2}^{2}-V(|\mathbf {r} _{1}-\mathbf {r} _{2}|)} 51:
be replaced with the reduced mass, if this is compensated by replacing the other mass with the sum of both masses. The reduced mass is frequently denoted by
3080:{\displaystyle I=m_{1}r_{1}^{2}+m_{2}r_{2}^{2}=R^{2}{\frac {m_{1}m_{2}^{2}}{(m_{1}+m_{2})^{2}}}+R^{2}{\frac {m_{1}^{2}m_{2}}{(m_{1}+m_{2})^{2}}}=\mu R^{2}.} 2315: 3693: 437: 140:, the equivalent one-body problem, with the position of one body with respect to the other as the unknown, is that of a single body of mass 3107: 3704:
Molecular Quantum Mechanics Parts I and II: An Introduction to Quantum Chemistry (Volume 1), P.W. Atkins, Oxford University Press, 1977,
3565: 2299:{\displaystyle \mathbf {r} _{1}={\frac {m_{2}\mathbf {r} }{m_{1}+m_{2}}},\;\mathbf {r} _{2}=-{\frac {m_{1}\mathbf {r} }{m_{1}+m_{2}}}.} 1019:{\displaystyle m_{1}\mathbf {a} _{1}=-m_{2}\mathbf {a} _{2}\;\;\Rightarrow \;\;\mathbf {a} _{2}=-{m_{1} \over m_{2}}\mathbf {a} _{1}} 3709: 2025: 2083: 354:{\displaystyle \mu =m_{1}\parallel m_{2}={\cfrac {1}{{\cfrac {1}{m_{1}}}+{\cfrac {1}{m_{2}}}}}={\cfrac {m_{1}m_{2}}{m_{1}+m_{2}}},} 557: 76: 784: 724: 2398: 1623: 848: 842:, the force that particle 2 exerts on particle 1 is equal and opposite to the force that particle 1 exerts on particle 2: 35:
when the particles are interacting with each other. Reduced mass allows the two-body problem to be solved as if it were a
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Reduced mass can be used in a multitude of two-body problems, where classical mechanics is applicable.
839: 662: 3549:{\displaystyle m_{\text{e}}\rightarrow {\frac {m_{\text{e}}m_{\text{p}}}{m_{\text{e}}+m_{\text{p}}}}} 1759: 1753: 104: 2019:
is a function as it is only dependent on the absolute distance between the particles. If we define
622: 3647: 3631: 2778: 709: 115: 40: 3742: 3679:, G.L. Trigg, VHC publishers, 1991, (Verlagsgesellschaft) 3-527-26954-1, (VHC Inc.) 0-89573-752-3 514: 3705: 3689: 2825: 36: 32: 2580: 2553: 2526: 2499: 1969: 3724: 2488: 1727: 1707: 82: 54: 3676: 2758: 1997: 3747: 3736: 3469: 505: 28: 2472:
is the reduced mass. Thus we have reduced the two-body problem to that of one body.
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and let the centre of mass coincide with our origin in this reference frame, i.e.
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Note that (since the derivative is a linear operator) the relative acceleration
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calculations, especially when the larger particle's exact mass is not known.
3200: 718:, the force exerted by a body (particle 2) on another body (particle 1) is: 2382:{\displaystyle {\mathcal {L}}={1 \over 2}\mu \mathbf {\dot {r}} ^{2}-V(r),} 364:
where the force on this mass is given by the force between the two bodies.
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Alternatively, a Lagrangian description of the two-body problem gives a
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The reduced mass is always less than or equal to the mass of each body:
494:{\displaystyle {\frac {1}{\mu }}={\frac {1}{m_{1}}}+{\frac {1}{m_{2}}}} 108: 20: 3458: 3181:{\displaystyle \Delta K={\frac {1}{2}}\mu v_{\rm {rel}}^{2}(e^{2}-1)} 2487: 1620:
This simplifies the description of the system to one force (since
3608:{\displaystyle m_{\text{p}}\rightarrow m_{\text{e}}+m_{\text{p}}} 3211:
Motion of two massive bodies under their gravitational attraction
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Dynamics and Relativity, J.R. Forshaw, A.G. Smith, Wiley, 2009,
3634:- the general operation, of which reduced mass is just one case 2067:{\displaystyle \mathbf {r} =\mathbf {r} _{1}-\mathbf {r} _{2}} 2143:{\displaystyle m_{1}\mathbf {r} _{1}+m_{2}\mathbf {r} _{2}=0} 2321: 1774: 609:{\displaystyle {\mu }={\frac {m_{1}}{2}}={\frac {m_{2}}{2}}} 2824:
This holds for a rotation around the center of mass. The
828:{\displaystyle \mathbf {F} _{21}=m_{2}\mathbf {a} _{2}} 768:{\displaystyle \mathbf {F} _{12}=m_{1}\mathbf {a} _{1}} 315: 286: 255: 243: 217: 205: 197: 185: 3559:
and the proton mass becomes the sum of the two masses
2462:{\displaystyle \mu ={\frac {m_{1}m_{2}}{m_{1}+m_{2}}}} 318: 289: 258: 246: 220: 208: 200: 188: 3568: 3481: 3372: 3224: 3110: 2834: 2781: 2761: 2686: 2613: 2583: 2556: 2529: 2502: 2401: 2318: 2163: 2086: 2028: 2000: 1972: 1941: 1771: 1730: 1710: 1673: 1626: 1345: 1305: 1268: 1045: 904: 851: 787: 727: 665: 625: 560: 517: 504:
which by re-arrangement is equivalent to half of the
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Two point masses rotating around the center of mass.
1660:{\displaystyle \mathbf {F} _{12}=-\mathbf {F} _{21}} 885:{\displaystyle \mathbf {F} _{12}=-\mathbf {F} _{21}} 3215:In the case of the gravitational potential energy 2745:{\displaystyle r_{2}=R{\frac {m_{1}}{m_{1}+m_{2}}}} 2672:{\displaystyle r_{1}=R{\frac {m_{2}}{m_{1}+m_{2}}}} 421:{\displaystyle \mu \leq m_{1},\quad \mu \leq m_{2}} 3607: 3548: 3430: 3351: 3180: 3101:, the change in kinetic energy can be written as 3079: 2813: 2767: 2744: 2671: 2596: 2569: 2542: 2515: 2461: 2381: 2298: 2142: 2066: 2006: 1985: 1958: 1924: 1736: 1716: 1696: 1659: 1609: 1328: 1291: 1251: 1018: 884: 827: 778:The force exerted by particle 1 on particle 2 is: 767: 684: 651: 608: 543: 493: 420: 353: 91: 63: 2550:such that they are co-linear, the two distances 2484:Moment of inertia of two point masses in a line 2309:Then substituting above gives a new Lagrangian 1299:is equal to the acceleration of the separation 39:. Note, however, that the mass determining the 3199:is the relative velocity of the bodies before 8: 3431:{\displaystyle m_{1}m_{2}=(m_{1}+m_{2})\mu } 2828:around this axis can be then simplified to 2228: 961: 960: 956: 955: 431:and has the reciprocal additive property: 3599: 3586: 3573: 3567: 3537: 3524: 3512: 3502: 3495: 3486: 3480: 3416: 3403: 3387: 3377: 3371: 3345: 3337: 3331: 3326: 3316: 3311: 3305: 3297: 3287: 3277: 3263: 3257: 3252: 3242: 3237: 3231: 3223: 3163: 3150: 3138: 3137: 3120: 3109: 3068: 3049: 3039: 3026: 3011: 3001: 2996: 2989: 2983: 2967: 2957: 2944: 2929: 2924: 2914: 2907: 2901: 2888: 2883: 2873: 2860: 2855: 2845: 2833: 2805: 2792: 2780: 2760: 2733: 2720: 2709: 2703: 2691: 2685: 2660: 2647: 2636: 2630: 2618: 2612: 2588: 2582: 2561: 2555: 2534: 2528: 2507: 2501: 2450: 2437: 2425: 2415: 2408: 2400: 2355: 2344: 2343: 2329: 2320: 2319: 2317: 2284: 2271: 2260: 2254: 2247: 2235: 2230: 2216: 2203: 2192: 2186: 2179: 2170: 2165: 2162: 2128: 2123: 2116: 2103: 2098: 2091: 2085: 2058: 2053: 2043: 2038: 2029: 2027: 1999: 1977: 1971: 1950: 1944: 1943: 1940: 1914: 1908: 1903: 1893: 1888: 1882: 1867: 1862: 1851: 1850: 1843: 1829: 1820: 1815: 1804: 1803: 1796: 1782: 1773: 1772: 1770: 1729: 1709: 1681: 1680: 1675: 1672: 1651: 1646: 1633: 1628: 1625: 1598: 1576: 1575: 1570: 1563: 1556: 1544: 1539: 1529: 1524: 1511: 1497: 1491: 1479: 1464: 1459: 1452: 1445: 1433: 1418: 1413: 1406: 1399: 1390: 1385: 1375: 1370: 1353: 1352: 1347: 1344: 1313: 1312: 1307: 1304: 1276: 1275: 1270: 1267: 1238: 1233: 1230: 1221: 1216: 1209: 1196: 1186: 1174: 1161: 1154: 1145: 1140: 1126: 1116: 1110: 1090: 1085: 1075: 1070: 1053: 1052: 1047: 1044: 1010: 1005: 996: 986: 980: 968: 963: 949: 944: 937: 921: 916: 909: 903: 876: 871: 858: 853: 850: 819: 814: 807: 794: 789: 786: 759: 754: 747: 734: 729: 726: 676: 664: 643: 630: 624: 595: 589: 575: 569: 561: 559: 535: 522: 516: 483: 474: 463: 454: 441: 439: 412: 392: 380: 337: 324: 319: 305: 295: 290: 283: 264: 259: 247: 240: 226: 221: 209: 202: 201: 189: 182: 173: 160: 148: 84: 56: 3675:Encyclopaedia of Physics (2nd Edition), 3655:, a relativistic equivalent used in the 2604:to the rotation axis may be found with 1697:{\displaystyle \mathbf {x} _{\rm {rel}}} 1329:{\displaystyle \mathbf {x} _{\rm {rel}}} 1292:{\displaystyle \mathbf {a} _{\rm {rel}}} 700:The equation can be derived as follows. 3668: 114:Reduced mass is particularly useful in 47:reduced. In the computation, one mass 101:a number of other physical quantities 7: 1036:between the two bodies is given by: 3442:Non-relativistic quantum mechanics 3145: 3142: 3139: 3111: 2496:In a system with two point masses 1959:{\displaystyle {\mathbf {r} }_{i}} 1688: 1685: 1682: 1583: 1580: 1577: 1360: 1357: 1354: 1320: 1317: 1314: 1283: 1280: 1277: 1060: 1057: 1054: 14: 685:{\displaystyle \mu \approx m_{2}} 33:system with two or more particles 3618:This idea is used to set up the 3327: 3312: 3253: 3238: 2349: 2346: 2261: 2231: 2193: 2166: 2124: 2099: 2054: 2039: 2030: 1945: 1904: 1889: 1856: 1853: 1809: 1806: 1676: 1647: 1629: 1571: 1540: 1525: 1460: 1414: 1386: 1371: 1348: 1308: 1271: 1234: 1217: 1141: 1086: 1071: 1048: 1006: 964: 945: 917: 872: 854: 815: 790: 755: 730: 126:Given two bodies, one with mass 77:standard gravitational parameter 1966:is the position vector of mass 401: 3579: 3492: 3422: 3396: 3338: 3306: 3268: 3264: 3232: 3228: 3175: 3156: 3046: 3019: 2964: 2937: 2373: 2367: 1919: 1915: 1883: 1879: 1550: 1520: 957: 652:{\displaystyle m_{1}\gg m_{2}} 27:is a measure of the effective 1: 2814:{\displaystyle R=r_{1}+r_{2}} 2775:is the sum of both distances 1336:between the two particles. 544:{\displaystyle m_{1}=m_{2}} 3764: 3096:coefficient of restitution 1751: 1029:The relative acceleration 707: 511:In the special case that 3657:post-Newtonian expansion 3638:Center-of-momentum frame 2015:). The potential energy 133:and the other with mass 3622:for the hydrogen atom. 3090:Collisions of particles 16:Effective inertial mass 3609: 3550: 3432: 3353: 3182: 3094:In a collision with a 3081: 2815: 2769: 2746: 2673: 2598: 2571: 2544: 2517: 2493: 2463: 2383: 2300: 2144: 2068: 2008: 1987: 1960: 1926: 1738: 1718: 1698: 1661: 1611: 1330: 1293: 1253: 1020: 886: 829: 769: 686: 653: 610: 545: 495: 422: 355: 93: 65: 3643:Momentum conservation 3610: 3551: 3433: 3354: 3183: 3082: 2816: 2770: 2747: 2674: 2599: 2597:{\displaystyle r_{2}} 2572: 2570:{\displaystyle r_{1}} 2545: 2543:{\displaystyle m_{2}} 2518: 2516:{\displaystyle m_{1}} 2491: 2464: 2384: 2301: 2145: 2069: 2009: 1988: 1986:{\displaystyle m_{i}} 1961: 1927: 1739: 1719: 1699: 1662: 1612: 1331: 1294: 1254: 1021: 887: 830: 770: 687: 654: 611: 546: 496: 423: 356: 94: 66: 3620:Schrödinger equation 3566: 3479: 3370: 3222: 3108: 2832: 2779: 2759: 2684: 2611: 2581: 2554: 2527: 2500: 2399: 2316: 2161: 2084: 2026: 1998: 1970: 1939: 1769: 1754:Lagrangian mechanics 1748:Lagrangian mechanics 1737:{\displaystyle \mu } 1728: 1717:{\displaystyle \mu } 1708: 1671: 1624: 1343: 1303: 1266: 1043: 902: 849: 785: 725: 663: 623: 558: 515: 438: 379: 147: 92:{\displaystyle \mu } 83: 64:{\displaystyle \mu } 55: 3648:Harmonic oscillator 3632:Parallel (operator) 3155: 3006: 2934: 2893: 2865: 1872: 1825: 716:Newton's second law 710:Newtonian mechanics 704:Newtonian mechanics 317: 288: 257: 245: 219: 207: 199: 187: 116:classical mechanics 79:is also denoted by 41:gravitational force 3605: 3546: 3428: 3349: 3178: 3133: 3077: 2992: 2920: 2879: 2851: 2811: 2765: 2742: 2669: 2594: 2567: 2540: 2513: 2494: 2459: 2379: 2296: 2140: 2064: 2004: 1983: 1956: 1922: 1849: 1802: 1734: 1714: 1694: 1667:), one coordinate 1657: 1607: 1326: 1289: 1249: 1016: 882: 840:Newton's third law 825: 765: 682: 649: 606: 541: 491: 418: 351: 344: 312: 276: 271: 252: 233: 214: 194: 89: 61: 3694:978-0-470-01460-8 3602: 3589: 3576: 3544: 3540: 3527: 3515: 3505: 3489: 3343: 3128: 3056: 2974: 2826:moment of inertia 2768:{\displaystyle R} 2740: 2667: 2457: 2352: 2337: 2291: 2223: 2007:{\displaystyle i} 1859: 1837: 1812: 1790: 1605: 1518: 1486: 1440: 1247: 1203: 1132: 1002: 604: 584: 489: 469: 449: 346: 316: 287: 278: 273: 256: 244: 235: 218: 206: 198: 186: 3755: 3712: 3702: 3696: 3686: 3680: 3673: 3614: 3612: 3611: 3606: 3604: 3603: 3600: 3591: 3590: 3587: 3578: 3577: 3574: 3555: 3553: 3552: 3547: 3545: 3543: 3542: 3541: 3538: 3529: 3528: 3525: 3518: 3517: 3516: 3513: 3507: 3506: 3503: 3496: 3491: 3490: 3487: 3437: 3435: 3434: 3429: 3421: 3420: 3408: 3407: 3392: 3391: 3382: 3381: 3358: 3356: 3355: 3350: 3344: 3342: 3341: 3336: 3335: 3330: 3321: 3320: 3315: 3309: 3303: 3302: 3301: 3292: 3291: 3278: 3267: 3262: 3261: 3256: 3247: 3246: 3241: 3235: 3187: 3185: 3184: 3179: 3168: 3167: 3154: 3149: 3148: 3129: 3121: 3086: 3084: 3083: 3078: 3073: 3072: 3057: 3055: 3054: 3053: 3044: 3043: 3031: 3030: 3017: 3016: 3015: 3005: 3000: 2990: 2988: 2987: 2975: 2973: 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234: 232: 231: 230: 215: 213: 203: 195: 193: 183: 178: 177: 165: 164: 98: 96: 95: 90: 75:), although the 70: 68: 67: 62: 37:one-body problem 3763: 3762: 3758: 3757: 3756: 3754: 3753: 3752: 3733: 3732: 3728:on HyperPhysics 3721: 3716: 3715: 3703: 3699: 3687: 3683: 3674: 3670: 3665: 3628: 3595: 3582: 3569: 3564: 3563: 3533: 3520: 3519: 3508: 3498: 3497: 3482: 3477: 3476: 3467: 3456: 3444: 3412: 3399: 3383: 3373: 3368: 3367: 3325: 3310: 3304: 3293: 3283: 3279: 3251: 3236: 3220: 3219: 3213: 3198: 3159: 3106: 3105: 3092: 3064: 3045: 3035: 3022: 3018: 3007: 2991: 2979: 2963: 2953: 2940: 2936: 2910: 2909: 2897: 2869: 2841: 2830: 2829: 2801: 2788: 2777: 2776: 2757: 2756: 2729: 2716: 2715: 2705: 2687: 2682: 2681: 2656: 2643: 2642: 2632: 2614: 2609: 2608: 2584: 2579: 2578: 2557: 2552: 2551: 2530: 2525: 2524: 2503: 2498: 2497: 2486: 2478: 2446: 2433: 2432: 2421: 2411: 2410: 2397: 2396: 2342: 2314: 2313: 2280: 2267: 2266: 2250: 2249: 2229: 2212: 2199: 2198: 2182: 2181: 2164: 2159: 2158: 2122: 2112: 2097: 2087: 2082: 2081: 2052: 2037: 2024: 2023: 1996: 1995: 1973: 1968: 1967: 1942: 1937: 1936: 1902: 1887: 1839: 1792: 1767: 1766: 1756: 1750: 1726: 1725: 1706: 1705: 1704:, and one mass 1674: 1669: 1668: 1645: 1627: 1622: 1621: 1594: 1590: 1569: 1559: 1558: 1538: 1523: 1507: 1503: 1493: 1475: 1471: 1458: 1448: 1447: 1429: 1425: 1412: 1402: 1401: 1384: 1369: 1346: 1341: 1340: 1306: 1301: 1300: 1269: 1264: 1263: 1232: 1215: 1205: 1192: 1182: 1181: 1170: 1157: 1156: 1139: 1122: 1112: 1103: 1099: 1084: 1069: 1046: 1041: 1040: 1035: 1004: 992: 982: 962: 943: 933: 915: 905: 900: 899: 870: 852: 847: 846: 813: 803: 788: 783: 782: 753: 743: 728: 723: 722: 712: 706: 698: 672: 661: 660: 639: 626: 621: 620: 591: 571: 556: 555: 531: 518: 513: 512: 479: 459: 436: 435: 408: 388: 377: 376: 370: 333: 320: 314: 301: 291: 285: 260: 254: 242: 222: 216: 204: 196: 184: 169: 156: 145: 144: 139: 132: 124: 81: 80: 53: 52: 17: 12: 11: 5: 3761: 3759: 3751: 3750: 3745: 3735: 3734: 3731: 3730: 3720: 3719:External links 3717: 3714: 3713: 3697: 3681: 3667: 3666: 3664: 3661: 3660: 3659: 3650: 3645: 3640: 3635: 3627: 3624: 3616: 3615: 3598: 3594: 3585: 3581: 3572: 3557: 3556: 3536: 3532: 3523: 3511: 3501: 3494: 3485: 3465: 3454: 3443: 3440: 3439: 3438: 3427: 3424: 3419: 3415: 3411: 3406: 3402: 3398: 3395: 3390: 3386: 3380: 3376: 3360: 3359: 3348: 3340: 3334: 3329: 3324: 3319: 3314: 3308: 3300: 3296: 3290: 3286: 3282: 3276: 3273: 3270: 3266: 3260: 3255: 3250: 3245: 3240: 3234: 3230: 3227: 3212: 3209: 3196: 3190: 3189: 3177: 3174: 3171: 3166: 3162: 3158: 3153: 3147: 3144: 3141: 3136: 3132: 3127: 3124: 3119: 3116: 3113: 3091: 3088: 3076: 3071: 3067: 3063: 3060: 3052: 3048: 3042: 3038: 3034: 3029: 3025: 3021: 3014: 3010: 3004: 2999: 2995: 2986: 2982: 2978: 2970: 2966: 2960: 2956: 2952: 2947: 2943: 2939: 2932: 2927: 2923: 2917: 2913: 2904: 2900: 2896: 2891: 2886: 2882: 2876: 2872: 2868: 2863: 2858: 2854: 2848: 2844: 2840: 2837: 2808: 2804: 2800: 2795: 2791: 2787: 2784: 2764: 2753: 2752: 2736: 2732: 2728: 2723: 2719: 2712: 2708: 2702: 2699: 2694: 2690: 2679: 2663: 2659: 2655: 2650: 2646: 2639: 2635: 2629: 2626: 2621: 2617: 2591: 2587: 2564: 2560: 2537: 2533: 2510: 2506: 2485: 2482: 2477: 2474: 2470: 2469: 2453: 2449: 2445: 2440: 2436: 2428: 2424: 2418: 2414: 2407: 2404: 2390: 2389: 2378: 2375: 2372: 2369: 2366: 2363: 2358: 2351: 2348: 2341: 2336: 2333: 2328: 2323: 2307: 2306: 2295: 2287: 2283: 2279: 2274: 2270: 2263: 2257: 2253: 2246: 2243: 2238: 2233: 2227: 2219: 2215: 2211: 2206: 2202: 2195: 2189: 2185: 2178: 2173: 2168: 2152: 2151: 2139: 2136: 2131: 2126: 2119: 2115: 2111: 2106: 2101: 2094: 2090: 2075: 2074: 2061: 2056: 2051: 2046: 2041: 2036: 2032: 2003: 1980: 1976: 1953: 1947: 1933: 1932: 1921: 1917: 1911: 1906: 1901: 1896: 1891: 1885: 1881: 1878: 1875: 1870: 1865: 1858: 1855: 1846: 1842: 1836: 1833: 1828: 1823: 1818: 1811: 1808: 1799: 1795: 1789: 1786: 1781: 1776: 1752:Main article: 1749: 1746: 1733: 1713: 1690: 1687: 1684: 1678: 1654: 1649: 1644: 1641: 1636: 1631: 1618: 1617: 1601: 1597: 1593: 1585: 1582: 1579: 1573: 1566: 1562: 1555: 1552: 1547: 1542: 1537: 1532: 1527: 1522: 1514: 1510: 1506: 1500: 1496: 1490: 1482: 1478: 1474: 1467: 1462: 1455: 1451: 1444: 1436: 1432: 1428: 1421: 1416: 1409: 1405: 1398: 1393: 1388: 1383: 1378: 1373: 1368: 1362: 1359: 1356: 1350: 1322: 1319: 1316: 1310: 1285: 1282: 1279: 1273: 1260: 1259: 1246: 1241: 1236: 1229: 1224: 1219: 1212: 1208: 1199: 1195: 1189: 1185: 1177: 1173: 1169: 1164: 1160: 1153: 1148: 1143: 1137: 1129: 1125: 1119: 1115: 1109: 1106: 1102: 1098: 1093: 1088: 1083: 1078: 1073: 1068: 1062: 1059: 1056: 1050: 1033: 1027: 1026: 1013: 1008: 999: 995: 989: 985: 979: 976: 971: 966: 959: 952: 947: 940: 936: 932: 929: 924: 919: 912: 908: 893: 892: 879: 874: 869: 866: 861: 856: 836: 835: 822: 817: 810: 806: 802: 797: 792: 776: 775: 762: 757: 750: 746: 742: 737: 732: 705: 702: 697: 694: 679: 675: 671: 668: 646: 642: 638: 633: 629: 617: 616: 603: 598: 594: 588: 583: 578: 574: 568: 564: 538: 534: 530: 525: 521: 502: 501: 486: 482: 478: 473: 466: 462: 458: 453: 448: 445: 429: 428: 415: 411: 407: 404: 400: 395: 391: 387: 384: 369: 366: 362: 361: 350: 340: 336: 332: 327: 323: 308: 304: 298: 294: 282: 267: 263: 250: 239: 229: 225: 212: 192: 181: 176: 172: 168: 163: 159: 155: 152: 137: 130: 123: 120: 103:). It has the 88: 60: 15: 13: 10: 9: 6: 4: 3: 2: 3760: 3749: 3746: 3744: 3741: 3740: 3738: 3729: 3727: 3723: 3722: 3718: 3711: 3710:0-19-855129-0 3707: 3701: 3698: 3695: 3691: 3685: 3682: 3678: 3672: 3669: 3662: 3658: 3654: 3651: 3649: 3646: 3644: 3641: 3639: 3636: 3633: 3630: 3629: 3625: 3623: 3621: 3596: 3592: 3583: 3570: 3562: 3561: 3560: 3534: 3530: 3521: 3509: 3499: 3483: 3475: 3474: 3473: 3471: 3470:hydrogen atom 3464: 3460: 3453: 3449: 3446:Consider the 3441: 3425: 3417: 3413: 3409: 3404: 3400: 3393: 3388: 3384: 3378: 3374: 3366: 3365: 3364: 3346: 3332: 3322: 3317: 3298: 3294: 3288: 3284: 3280: 3274: 3271: 3258: 3248: 3243: 3225: 3218: 3217: 3216: 3210: 3208: 3204: 3202: 3195: 3172: 3169: 3164: 3160: 3151: 3134: 3130: 3125: 3122: 3117: 3114: 3104: 3103: 3102: 3100: 3097: 3089: 3087: 3074: 3069: 3065: 3061: 3058: 3050: 3040: 3036: 3032: 3027: 3023: 3012: 3008: 3002: 2997: 2993: 2984: 2980: 2976: 2968: 2958: 2954: 2950: 2945: 2941: 2930: 2925: 2921: 2915: 2911: 2902: 2898: 2894: 2889: 2884: 2880: 2874: 2870: 2866: 2861: 2856: 2852: 2846: 2842: 2838: 2835: 2827: 2822: 2806: 2802: 2798: 2793: 2789: 2785: 2782: 2762: 2734: 2730: 2726: 2721: 2717: 2710: 2706: 2700: 2697: 2692: 2688: 2680: 2661: 2657: 2653: 2648: 2644: 2637: 2633: 2627: 2624: 2619: 2615: 2607: 2606: 2605: 2589: 2585: 2562: 2558: 2535: 2531: 2508: 2504: 2490: 2483: 2481: 2475: 2473: 2451: 2447: 2443: 2438: 2434: 2426: 2422: 2416: 2412: 2405: 2402: 2395: 2394: 2393: 2376: 2370: 2364: 2361: 2356: 2339: 2334: 2331: 2326: 2312: 2311: 2310: 2293: 2285: 2281: 2277: 2272: 2268: 2255: 2251: 2244: 2241: 2236: 2225: 2217: 2213: 2209: 2204: 2200: 2187: 2183: 2176: 2171: 2157: 2156: 2155: 2137: 2134: 2129: 2117: 2113: 2109: 2104: 2092: 2088: 2080: 2079: 2078: 2059: 2049: 2044: 2034: 2022: 2021: 2020: 2018: 2014: 2001: 1993:(of particle 1978: 1974: 1951: 1909: 1899: 1894: 1876: 1873: 1868: 1863: 1844: 1840: 1834: 1831: 1826: 1821: 1816: 1797: 1793: 1787: 1784: 1779: 1765: 1764: 1763: 1761: 1755: 1747: 1745: 1731: 1711: 1652: 1642: 1639: 1634: 1599: 1595: 1591: 1564: 1560: 1553: 1545: 1535: 1530: 1512: 1508: 1504: 1498: 1494: 1488: 1480: 1476: 1472: 1465: 1453: 1449: 1442: 1434: 1430: 1426: 1419: 1407: 1403: 1396: 1391: 1381: 1376: 1366: 1339: 1338: 1337: 1244: 1239: 1227: 1222: 1210: 1206: 1197: 1193: 1187: 1183: 1175: 1171: 1167: 1162: 1158: 1151: 1146: 1135: 1127: 1123: 1117: 1113: 1107: 1104: 1100: 1096: 1091: 1081: 1076: 1066: 1039: 1038: 1037: 1032: 1011: 997: 993: 987: 983: 977: 974: 969: 950: 938: 934: 930: 927: 922: 910: 906: 898: 897: 896: 877: 867: 864: 859: 845: 844: 843: 841: 838:According to 820: 808: 804: 800: 795: 781: 780: 779: 760: 748: 744: 740: 735: 721: 720: 719: 717: 711: 703: 701: 695: 693: 677: 673: 669: 666: 644: 640: 636: 631: 627: 601: 596: 592: 586: 581: 576: 572: 566: 562: 554: 553: 552: 536: 532: 528: 523: 519: 509: 507: 506:harmonic mean 484: 480: 476: 471: 464: 460: 456: 451: 446: 443: 434: 433: 432: 413: 409: 405: 402: 398: 393: 389: 385: 382: 375: 374: 373: 367: 365: 348: 338: 334: 330: 325: 321: 306: 302: 296: 292: 280: 265: 261: 248: 237: 227: 223: 210: 190: 179: 174: 170: 166: 161: 157: 153: 150: 143: 142: 141: 136: 129: 121: 119: 117: 112: 110: 107:of mass, and 106: 102: 86: 78: 74: 58: 50: 46: 42: 38: 34: 30: 29:inertial mass 26: 22: 3726:Reduced Mass 3725: 3700: 3684: 3671: 3617: 3558: 3462: 3451: 3445: 3361: 3214: 3205: 3193: 3191: 3098: 3093: 2823: 2754: 2495: 2479: 2476:Applications 2471: 2391: 2308: 2153: 2076: 2016: 1994: 1934: 1757: 1619: 1261: 1030: 1028: 894: 837: 777: 713: 699: 618: 510: 503: 430: 371: 363: 134: 127: 125: 113: 48: 44: 25:reduced mass 24: 18: 3677:R.G. Lerner 895:Therefore: 3737:Categories 3663:References 3653:Chirp mass 1760:Lagrangian 708:See also: 696:Derivation 368:Properties 105:dimensions 3743:Mechanics 3580:→ 3493:→ 3468:) in the 3426:μ 3323:− 3275:− 3249:− 3201:collision 3170:− 3131:μ 3112:Δ 3062:μ 2403:μ 2362:− 2350:˙ 2340:μ 2245:− 2050:− 1900:− 1874:− 1857:˙ 1810:˙ 1732:μ 1712:μ 1643:− 1536:− 1443:− 1382:− 1245:μ 1082:− 978:− 958:⇒ 931:− 868:− 670:≈ 667:μ 637:≫ 563:μ 447:μ 406:≤ 403:μ 386:≤ 383:μ 167:∥ 151:μ 87:μ 59:μ 3626:See also 3448:electron 122:Equation 99:(as are 659:, then 109:SI unit 21:physics 3708:  3692:  3461:(mass 3459:proton 3457:) and 3450:(mass 3192:where 2755:where 2392:where 1935:where 714:Using 2154:then 31:of a 3748:Mass 3706:ISBN 3690:ISBN 2577:and 2523:and 111:kg. 3197:rel 1762:of 1034:rel 619:If 49:can 45:not 43:is 19:In 3739:: 3203:. 2821:. 1744:. 1653:21 1635:12 1240:12 1067::= 878:21 860:12 796:21 736:12 692:. 551:: 508:. 118:. 73:mu 23:, 3601:p 3597:m 3593:+ 3588:e 3584:m 3575:p 3571:m 3539:p 3535:m 3531:+ 3526:e 3522:m 3514:p 3510:m 3504:e 3500:m 3488:e 3484:m 3466:p 3463:m 3455:e 3452:m 3423:) 3418:2 3414:m 3410:+ 3405:1 3401:m 3397:( 3394:= 3389:2 3385:m 3379:1 3375:m 3347:, 3339:| 3333:2 3328:r 3318:1 3313:r 3307:| 3299:2 3295:m 3289:1 3285:m 3281:G 3272:= 3269:) 3265:| 3259:2 3254:r 3244:1 3239:r 3233:| 3229:( 3226:V 3194:v 3188:, 3176:) 3173:1 3165:2 3161:e 3157:( 3152:2 3146:l 3143:e 3140:r 3135:v 3126:2 3123:1 3118:= 3115:K 3099:e 3075:. 3070:2 3066:R 3059:= 3051:2 3047:) 3041:2 3037:m 3033:+ 3028:1 3024:m 3020:( 3013:2 3009:m 3003:2 2998:1 2994:m 2985:2 2981:R 2977:+ 2969:2 2965:) 2959:2 2955:m 2951:+ 2946:1 2942:m 2938:( 2931:2 2926:2 2922:m 2916:1 2912:m 2903:2 2899:R 2895:= 2890:2 2885:2 2881:r 2875:2 2871:m 2867:+ 2862:2 2857:1 2853:r 2847:1 2843:m 2839:= 2836:I 2807:2 2803:r 2799:+ 2794:1 2790:r 2786:= 2783:R 2763:R 2735:2 2731:m 2727:+ 2722:1 2718:m 2711:1 2707:m 2701:R 2698:= 2693:2 2689:r 2662:2 2658:m 2654:+ 2649:1 2645:m 2638:2 2634:m 2628:R 2625:= 2620:1 2616:r 2590:2 2586:r 2563:1 2559:r 2536:2 2532:m 2509:1 2505:m 2452:2 2448:m 2444:+ 2439:1 2435:m 2427:2 2423:m 2417:1 2413:m 2406:= 2377:, 2374:) 2371:r 2368:( 2365:V 2357:2 2347:r 2335:2 2332:1 2327:= 2322:L 2294:. 2286:2 2282:m 2278:+ 2273:1 2269:m 2262:r 2256:1 2252:m 2242:= 2237:2 2232:r 2226:, 2218:2 2214:m 2210:+ 2205:1 2201:m 2194:r 2188:2 2184:m 2177:= 2172:1 2167:r 2150:, 2138:0 2135:= 2130:2 2125:r 2118:2 2114:m 2110:+ 2105:1 2100:r 2093:1 2089:m 2060:2 2055:r 2045:1 2040:r 2035:= 2031:r 2017:V 2002:i 1979:i 1975:m 1952:i 1946:r 1920:) 1916:| 1910:2 1905:r 1895:1 1890:r 1884:| 1880:( 1877:V 1869:2 1864:2 1854:r 1845:2 1841:m 1835:2 1832:1 1827:+ 1822:2 1817:1 1807:r 1798:1 1794:m 1788:2 1785:1 1780:= 1775:L 1689:l 1686:e 1683:r 1677:x 1648:F 1640:= 1630:F 1600:2 1596:t 1592:d 1584:l 1581:e 1578:r 1572:x 1565:2 1561:d 1554:= 1551:) 1546:2 1541:x 1531:1 1526:x 1521:( 1513:2 1509:t 1505:d 1499:2 1495:d 1489:= 1481:2 1477:t 1473:d 1466:2 1461:x 1454:2 1450:d 1435:2 1431:t 1427:d 1420:1 1415:x 1408:2 1404:d 1397:= 1392:2 1387:a 1377:1 1372:a 1367:= 1361:l 1358:e 1355:r 1349:a 1321:l 1318:e 1315:r 1309:x 1284:l 1281:e 1278:r 1272:a 1235:F 1228:= 1223:1 1218:a 1211:1 1207:m 1198:2 1194:m 1188:1 1184:m 1176:1 1172:m 1168:+ 1163:2 1159:m 1152:= 1147:1 1142:a 1136:) 1128:2 1124:m 1118:1 1114:m 1108:+ 1105:1 1101:( 1097:= 1092:2 1087:a 1077:1 1072:a 1061:l 1058:e 1055:r 1049:a 1031:a 1012:1 1007:a 998:2 994:m 988:1 984:m 975:= 970:2 965:a 951:2 946:a 939:2 935:m 928:= 923:1 918:a 911:1 907:m 873:F 865:= 855:F 821:2 816:a 809:2 805:m 801:= 791:F 761:1 756:a 749:1 745:m 741:= 731:F 678:2 674:m 645:2 641:m 632:1 628:m 602:2 597:2 593:m 587:= 582:2 577:1 573:m 567:= 537:2 533:m 529:= 524:1 520:m 485:2 481:m 477:1 472:+ 465:1 461:m 457:1 452:= 444:1 414:2 410:m 399:, 394:1 390:m 349:, 339:2 335:m 331:+ 326:1 322:m 307:2 303:m 297:1 293:m 281:= 266:2 262:m 249:1 238:+ 228:1 224:m 211:1 191:1 180:= 175:2 171:m 162:1 158:m 154:= 138:2 135:m 131:1 128:m 71:(

Index

physics
inertial mass
system with two or more particles
one-body problem
gravitational force
mu
standard gravitational parameter
a number of other physical quantities
dimensions
SI unit
classical mechanics
harmonic mean
Newtonian mechanics
Newton's second law
Newton's third law
Lagrangian mechanics
Lagrangian

moment of inertia
coefficient of restitution
collision
electron
proton
hydrogen atom
Schrödinger equation
Parallel (operator)
Center-of-momentum frame
Momentum conservation
Harmonic oscillator
Chirp mass

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