A) \[\frac{22}{3}cm\]
B) \[\frac{40}{3}cm\]
C) \[\frac{20}{3}cm\]
D) \[\frac{22}{5}cm\]
E) \[\frac{26}{5}cm\]
Correct Answer: B
Solution :
Let initial velocity of body at point A is v, AB is 40cm. From \[{{v}^{2}}={{u}^{2}}-2as\] \[\Rightarrow \] \[{{\left( \frac{v}{2} \right)}^{2}}={{v}^{2}}-2a\times 40\] Or \[a=\frac{3{{v}^{2}}}{320}\] Let on penetrating 40 cm in a wooden block, the body moves x distance from B to C. So, for B to C \[u=\frac{v}{2},v=0\] \[s=x,a=\frac{3{{v}^{2}}}{320}\] (deceleration) \[\therefore \] \[{{(0)}^{2}}={{\left( \frac{v}{2} \right)}^{2}}-2\times \frac{3{{v}^{2}}}{320}\times x\] Or \[x=\frac{40}{3}cm\]You need to login to perform this action.
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