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9th Class Science Force and laws of motion Question Bank Force And Laws Of Motion IIT JEE Objective Problems

  • question_answer
    A vehicle of 100 kg is moving with a velocity of 5m/ s. To stop it in 1/10 s, the required force in opposite direction is :

    A)  5000 N                

    B)  500 N

    C)  50 N                                     

    D)  1000 N

    Correct Answer: A

    Solution :

       Given, \[m=100\text{ }kg\] Initial velocity (u) = 5 m/s, time \[(t)=\frac{1}{10}s\] The vehicle is coming to rest (v) = 0, F =? we know, \[vu=at\] \[\Rightarrow \] \[05=a\times \frac{1}{10}\]\[\Rightarrow \]\[a=-50\,m/{{s}^{2}}\] we also know that, \[F=ma\]      .................(1) substituting all the above values in equation (1), we get \[\Rightarrow \] \[F=100\times 50=5000\text{ }N\] (\[\because \] the negative sign indicates the force is in opposite direction) \[\therefore \] \[F=5000\text{ }N\]        


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