JEE Main & Advanced Physics NLM, Friction, Circular Motion Question Bank Second Law of Motion

  • question_answer
    A coin is dropped in a lift. It takes time \[{{t}_{1}}\] to reach the floor when lift is stationary. It takes time \[{{t}_{2}}\] when lift is moving up with constant acceleration. Then 

    A)                         \[{{t}_{1}}>{{t}_{2}}\]            

    B)                           \[{{t}_{2}}>{{t}_{1}}\]            

    C)             \[{{t}_{1}}={{t}_{2}}\]

    D)                           \[{{t}_{1}}>>{{t}_{2}}\]

    Correct Answer: A

    Solution :

                                For stationary lift \[{{t}_{1}}=\sqrt{\frac{2h}{g}}\]             and when the lift is moving up with constant acceleration \[{{t}_{2}}=\sqrt{\frac{2h}{g+a}}\] \[\therefore \ \ {{t}_{1}}>{{t}_{2}}\]            


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