A) 1 cm
B) 2 cm
C) 3 cm
D) 4 cm
Correct Answer: A
Solution :
Let initial velocity of body at point A be v, AB is 3 cm. From \[{{v}^{2}}={{u}^{2}}-2\]as \[{{\left( \frac{v}{2} \right)}^{2}}={{v}^{2}}-2a\times 3\] \[a=\frac{{{v}^{2}}}{8}\] Let after penetrating 3 cm in a wooden block, the body moves x distance from B to C and comes to rest. So, for B to C \[u=\frac{v}{2},\,\,v=0\], \[s=x,\,a=\frac{{{v}^{2}}}{8}\] (retardation) \[\therefore \] \[{{(0)}^{2}}={{\left( \frac{V}{2} \right)}^{2}}-2.\frac{{{V}^{2}}}{8}.\,x\] \[x=1\,cm\] NOTE Here, it is assumed that retardation is uniform.You need to login to perform this action.
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