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s:recoil of President the effect of a singleAot '`Shooting at taped melons t 'dt:iVen away from:the, rifle •„eotion. We. analyse previous •er film by cri and failure of t 41,60,0h* „4., Alvaro-z)` .clit6h) Aze .listed here is meant, to indicate content' is the work of k, The tests of a hypothesis by L.W. 4 whia the report to yen fOr: your el-Lab:it*. flents. of article on the- .p ygic's 'of,the problem to 1 for physicists. i...1e 0 distribute port to studentsOf't sport after been considered, and after ort version e Phyttics Today article well, picked up by Ahis Material strictly confidential at#this time. -t 1970 ,eastrertypy aer,the Report of the aarran C-laission on Der busheid ow, that s;lerpky, Dbmwrneadaltion of,Proidont Irisready bas booth. question of the number nairaiwoulse ~U. & looked Itsettelt 11101.4. .001-410411sWer the sate fired. If shots oar from two dIffc-rent directions, notion is *nigh* mast ha* isemmitia4 /21110‘ shit ligpeleals,heme boom a conspiracy. Critics of the Whrren hour: have drawn from the treat, es this Dr...46 J4 IMOOWN401161C, 41, 0MOOtkagainst the Commission's conclusions from the principal physical ph ysiclat adlimarelegists 100004 of the assassination, a 25-second color film taken by amateur photographer &simony lbw** hit* a projarte3044 is. Uproar* given a sale& that deratiom as that of the RweJwwtillow At a shoot* , the ducks fall 404,4,0011,the sat detailed study yet published of this and other photographs of martini s. athwart if someone is shot, advise eat strelmealoWthe of rersiX will* 047 400 ,,,igio.empoggiaamien is ALE &mood* ew Xnllss, by Haver/oral philosophy professor toward - the (Page Deseahasis added) • ' • 1 . ,,-. ifhSelefs Thompson (Bernard Geis, 1967). Thompson analysed in detail the one part I &ow of Dr.Abadamehterest in the &men Import frOhis ansayll• et 'Caw Segroder film Which appears most strikingly to contradict the Commission's the impaar !Dim is 1969. bed found :rano that Zaprudor bad jiggle* bas • agolussion that all of the shots were fired from behind and above the President. tamer*, preably, in rseetia to a shot, at a point before the Commission thought ppm* is obviously driven backward and to the left by the shot which strikes the first shat hie han fitiS. (A1ra:a oamsunioated these observations to 'bee im tho head, producing a massive and fatal wound. As we will discuss below, triads of his at Cis 1Mheare prominatly featured in the "CBS Report", a the Wren Commission ignored this evidence, but several critics have claimed that for-tarprogrup pr Lift the saner of 1967.) . lb had agreed that Cie had first two bah mad motion is in itself evidence of a shot from the right front (the adoestalsyhaiehod tistiiiiiikep of the bacroardatiom after the fatal' abet, aid direrWa of 4 the "grassy knoll"). Thompson measured the motion of the President's I told [loses of the detailed steely of this point in lbeasee's Oak. Iodated 4 forward acceleration followed Minot immediately by a comparably After reeding thempsom's work, Alvaro pointed nut to me that the fist Weeeleration, leading to the backwards motion which is visible bachamadation eight bo Jot what be would expect from a single shot from the Italie of the film. This, Thompson concluded, was evidence that rear, ender certain cireostances. As Dr, Riddle woidesilstodey realised, asseratisor,, - leo dUteripat shots bed struck the President at about the same time - one from of momenta has staple and easily predictable oonsogoemess only fer'arogigema year, and another from the front. of rigid or nearly rigid bodies. (Riddle did qualify the osmsi t,,;,410spite the inherent implausibility of two shots striking the President pr r.ewrwop tho "wool direction" of the inched! ice, 40144 tenth of s second of each ether, it was not at all obvious that the Arid easily lie bashardiation-auld be owalletont with a shot'from any direction emapt the frog. Thespeon considered 'ejected the most obvious alternative explanationet that Kennedy's head struck suns surface and bounced back, that Mrs. Kennedy pulled the ems sor,tmo from aft*10aigt4 'Oar's suggested that the lUeereingiilmotie, •■ • - 3 - energy of the bullet could be made available to drive enough material forward, mator7 effect. („In a rigid body eellieion where the billet is stopped in the fast enough, so that its forward momentum was greater than the forward momentum Agree. almost all of the Incident kinetic energy would be lost as heat.) • . carried in by the bullet: if this were the case, the law of conservation of Just 6ecausi'1 1.1rp6theeis :is consistent with momentum and energy conservation momentum would require the remaining part of the head to recoil backwards - of' not 4140) tt is SlAysimaiiit pqsaible. Some dynamical mechanism is needed toward the gun. plain hes„there can tie iier. momentum in the direction of the bullet When Alvarez saw Thompson's quantitative analysis and graphs of the rresident.O. ftterlt h4 ittteractedSith the-itarget than before. (Once this is understood. motion, he realized for the first time that he had to treat the 7retregride tAie clear that the part of the target which is not driven forward must recoil motion" seriously, With some simple "back of the envelope" calculations (using bacia.) This is not as unlikely as it:may at first seem. All that is required a one-dimensional model for the collision) he quickly showed that the observed is that the bullet, As it is slowed down, pulls material from, the target along motion could easily be made consistent with conservation of momentum and enerOy. with it, at speeds up-to that of the bullet. A 160-grain bullet traveling at 1S00 feet per second carries shout 40 foot-pounds We felt that no such hypothesis could be taken too seriously unless it per second of momentum. (These numbers correspond roughly to those for the bullet was experimentally verifiable, especially since it violated our intuitive notions. allegedly used in the assassination, but for this semi-quantitative argument Alvarez asked Sharon (Buck) Buckingham, an expert with guns (who, along with approximate values are suffioient. See Appendix 1 for more details.) Thompson Alvarez and me, works at the University of California Lawrence Radiation Lab) to measured the backwards velocity of Kennedy's head after the shot to be about set up an experiment to test this theory. 3uckinmham thought it seemed unlikely 1.6 feet per second. Estimating the weight of the recoiling part of the heal and 'o work, but agreed to try. The ran -emaster at the San Leandro rifle range was body at 20 pounds (that is, recoil momentum = 32 foot-pounds per second), we see just as skeptical, but generously arranged for us to use the range. Buckingham that Newton's lairs (conservation of momentum) require that 40 + 32 = 72 foot-oeunds shot at eight targets of various kinds, and reported that Alvarez' hypothesis per second of momentum be carried forward by the fragments of bone, metal, and did seem to work. We decided that Photographs were essential, and returned to tissue which are driven forward. (For example, 1 pound of matter goin' at about the rifle range some months later with a full experimental team. (In addition 70 feet per second would suffice.) It is probably not possible to estimate to Or. Alvarez and Buck Buckingham, the team consisted of Dewey Machinelli as accurately the amount and speed of the forward-going fragments, but it does not marksman, and Don Olson and myself as photographers and "consultants" on the seem inconsistent with the Zapruder film and other evidence for them to he Warren Report.) We set up a remote-controlled 8:mm, movie camera and recorded carrying about 70 foot-pounds per second of momentum forward. Since the bullet the impact of a bullet on several water- and gelatin-filled containers.' We mass (weight) is so small compared to the mass of the target or the fraoments. found that the results were inconclusive with such targets, and that melons (as there is no difficulty in reconciling this hypothesis with the law o' ener,7, had been used in Bmckingham's first tests) were the best for simulating what we conservation -- most of the incident ki,netic energy (enercy of motion) can he thought we saw in the Zapruder film. After the melon season opened, we went to dissipated as heat, with plenty left over to produce the observed "rocket San Leandro a third We found that We meads/mite enhaistently prodaoe the ''sosexpected" result. Warren Commission, with frame. 314 and 315 interchanged. some were published a backwards retail. Sighre I shown clearly the effiet we were looking for. in color in the October 2, 1964 issue of Life.) The target is a 3-pound hemsydew melon, well wrapped with 1-inch Scotch The results shown in Figure 1 are not just a flukes in six of the seven filament tape. A 30.06 rifle fired a 150-grain round-nose reloaded bullet tests we filmed using taped melons, wp observed recoil toward the gun. The part from a pron.* position about 35 yards to the the rights the film was taken at of the melon that recoiled typically consisted of the taped shell, with distinct 24 frames per second from a position perpendicular to the line of flight of entry and exit holes up to a few inches in size. and perhaps one-half to two- the bullet. (The target was planed a couple of feet above 'round level so thirds of the interior.