NEET Sample Paper NEET Sample Test Paper-71

  • question_answer
    A car is moving along a straight horizontal road with a speed \[{{\nu }_{0}}\]. If the coefficient of friction between the tyres and the road is \[\mu \] the shortest distance in which the car can be stopped is

    A) \[\frac{{{\nu }_{0}}^{2}}{2\,\mu g}\]  

    B) \[\frac{{{\nu }_{0}}^{{}}}{\mu g}\]

    C) \[{{\left( \frac{{{\nu }_{0}}^{{}}}{\mu g} \right)}^{2}}\]                    

    D) \[\frac{{{\nu }_{0}}^{{}}}{\mu }\]

    Correct Answer: A

    Solution :

    Retarding force \[\operatorname{F}=ma = \mu R\,\,=\,\,\mu mg\,\,\,\,\] \[\therefore \,\,\,\,\,\,a=\mu g\] Now from equation of motion \[{{\operatorname{v}}^{2}}={{u}^{2}}- 2as\] \[\Rightarrow \,\,\,\,0={{u}^{2}}-2as\,\,\,\,\,\Rightarrow \,\,\,\,\,s=\frac{{{u}^{2}}}{2a}=\frac{{{u}^{2}}}{2\mu g}\] \[\therefore \,\,\,\,\,\,s=\frac{v_{0}^{2}}{2\mu g}\]


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