Manipal Medical Manipal Medical Solved Paper-2008

  • question_answer
    A car of mass m moves in a horizontal circular path of radius r m. At an instant its speed is v m/s and is increasing at a rate of\[a\text{ }m/{{s}^{2}}\]. Then the acceleration of the car is

    A)  \[\frac{{{v}^{2}}}{r}\]

    B)  \[a\]

    C)  \[\sqrt{{{a}^{2}}+{{\left( \frac{{{v}^{2}}}{r} \right)}^{2}}}\]

    D)  \[\sqrt{u+\frac{{{v}^{2}}}{r}}\]

    Correct Answer: C

    Solution :

     Radial acceleration\[{{a}_{r}}=\frac{{{v}^{2}}}{r}\] Tangential acceleration \[{{a}_{t}}=a\] \[\therefore \]Resultant acceleration \[a=\sqrt{a_{r}^{2}+a_{t}^{2}+2{{a}_{r}}{{a}_{t}}\cos \theta }\] But here \[\theta =90{}^\circ \] \[\therefore \] \[\cos \theta =\cos 90{}^\circ =0\] and \[a=\sqrt{a_{r}^{2}+a_{t}^{2}}=\sqrt{{{\left( \frac{{{v}^{2}}}{r} \right)}^{2}}+{{a}^{2}}}\]


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