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--- book:chap5:spatial-extension [2021/10/07 05:16] – jv
+++ book:chap5:spatial-extension [2022/01/02 15:50] (current) – jv
@@ Line 1: / Line 1: @@
 ====== 5. Impact of Spatial Extension ======
+<WRAP group>
+<WRAP third column #fig_EXP-dropletExplosion>
+{{Laser_impact_on_a_drop.jpg}}
+Figure 5.1: Impact of a laser pulse on a microdrop of opaque liquid that is thus blown up;
+[[http://link.aps.org/doi/10.1103/PhysRevApplied.3.044018 |Klein, et al, Phys. Rev. Appl. 3 (2015) 044018]]
+</WRAP>
+<WRAP third column #fig_EXP-clackers>
+{{Mensen_met_een_klik_klak_Amsterdam_Bestanddeelnr_924-8383.jpg}}
+Figure 5.2: Girl playing with clackers.
+[[https://commons.wikimedia.org/wiki/File:Mensen_met_een_klik_klak_Amsterdam,_Bestanddeelnr_924-8383.jpg |Punt/Anefo, Amsterdam 1971]], [[https://creativecommons.org/licenses/ |CC0]]
+</WRAP>
+<WRAP third column #EXP-reachTennisBall>
+{{Gluten_free_speed_-_Flickr_-_chascow.jpg}}
+Figure 5.3: Man running to return a tennis ball.
+[[https://commons.wikimedia.org/wiki/File:Gluten_free_speed_-_Flickr_-_chascow.jpg |Charlie Cowins from Belmont, NC, USA]], [[https://creativecommons.org/licenses/by/2.0 |CC by 2.0]]
+</WRAP>
+</WRAP>
+In [[book:chap4:eom-ode|Chapter 4]] we discussed the motion of point particles.
+However, in our environment the spatial extension of particles in crucial.
+Physical objects always keep a minimum distance due to their spatial extension.
+When they had zero extension,
+one could neither blow up water droplets by impact with a laser ([[#fig_EXP-dropletExplosion |Figure 5.1]]),
+nor work clackers ([[#fig_EXP-clackers |Figure 5.2]]) or hit a ball with a tennis racket ([[#fig_EXP-reachTennisBall |Figure 5.3]]).
+Even giving spin to a ball only works due to the distance between the surface of the racket
+and the center of the ball.
+At the end of this chapter we will be able to discuss the evolution of balls with spin,
+and their reflections from flat surfaces.
+Why is spin of so much importance in table tennis?
+How can a wingman score a goal in Handball,
+even when the goal keeper is fully blocking the direct path to the goal?((See [[https://en.wikipedia.org/wiki/Handball#Formations|Wikipedia's description of Handball formations]] and this [[https://de.wikipedia.org/wiki/Kreisl%C3%A4ufer_(Handball)#/media/Datei:Bertrand_Gille_02.jpg|picture of an attack by Bertrand Gille]], the IHF World Player of the Year 2002.))
+----
+  * [[ 5.1 Motivation and outline | 5.1 Motivation and outline: How do particles collide?]]
+  * [[ 5.2 Collisions of particles | 5.2 Collisions of hard-ball particles]]
+  * [[ 5.3 Volume integrals | 5.3 Volume integrals — A professor falling through Earth]]
+  * [[ 5.4 Center of mass and spin | 5.4 Center of mass and spin of extended objects]]
+  * [[ 5.5 Bodies with internal degrees of freedom | 5.5 Bodies with internal degrees of freedom: Revisiting mobiles]]
+  * [[ 5.6 Worked example | 5.6 Worked example: Reflection of balls]]
+  * [[ 5.7 Problems | 5.7 Problems]]
 The PDF file of the chapter is available  {{ book:chap5:2021_jv_unil_mechanics_chap05.pdf |here}}.