A) \[-\frac{5{{\ell }_{2}}}{2}m/s\]
B) \[-\frac{2{{\ell }_{2}}}{5}m/s\]
C) \[-\frac{{{\ell }_{2}}}{2}m/s\]
D) \[-\frac{{{\ell }_{2}}}{5}m/s\]
Correct Answer: B
Solution :
[b] Let BP=x. From similar triangle property, we get \[\frac{AO}{{{l}_{1}}}=\frac{{{l}_{2}}}{x}\] or \[AO=\frac{{{l}_{1}}{{l}_{2}}}{x}\] or \[\frac{d(AO)}{dt}=\frac{-{{l}_{1}}{{l}_{2}}}{{{x}^{2}}}\frac{dx}{dt}\] When \[x=\frac{{{l}_{1}}}{2},\frac{d(AO)}{dt}=-\frac{2{{l}_{2}}}{5}m/s.\]You need to login to perform this action.
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