A bullet fired into a fixed target loses half of its velocity after penetrating 3cm. How much further it will penetrate before coming to rest assuming that it faces constant resistance to motion ?
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Updated on : 2022-09-05
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Correct option is C)
Case I :
[2u]2−u2=2.a.3 or −43u2=2.a.3⇒a=−8u2 Case II : 0−[2u]2=2.a.x or −4u2=2[−8u2]×x ⇒x=1cm Alternative method : Let K be the initial energy and F be the resistive force. Then according to work-energy theorem, W=ΔK i.e., 3F=21mv2−21m[2v]2 3F=21mv2[1−41] 3F=43[21mv2] ............(1) and Fx=21m[2v]2−21m(0)2 i.e., 41[21mv2]=Fx .........(2) Comparing eqns. (1) and (2) F=Fx or x=1cm
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