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Amount of energy loss (in J) in the collision is:
17 to 18
Key idea: energy loss =Kparticle, before-Kparticle, after-Kdisk; Kdisk=1.529 J from angular-momentum conservation about C (previous part).
Ki= 12 0.02 1002=100 J; Kf= 12 0.02 902=81 J.
Loss =100-81-1.53=17.47 J.
Answer: 17.47 (accepted range 17 to 18)
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