JEE Main & Advanced Sample Paper JEE Main Sample Paper-6

  • question_answer
    Directions: Question No. 30 are Assertion- Reaction type. Each of these contains tow statements Statement I (Assertion), Statement II (Reason). Each of these questions also has four alternative choices, only on of which is correct. You have to select the correct choices from the codes a, b, c and d given below:   
    Statement I: The safe velocity limit for taking- a turn on an unbanked road is \[v=\sqrt{\mu rg}.\]
    Statement II: Banking of roads will increase the value of limiting velocity.

    A)  Statement I is true; Statement B is true; Statement B is not a correct explanation for Statement I,

    B)  Statement I is true; Statement II is false.

    C)  Statement I is false; Statement II is true.

    D)  Statement I is true; Statement II is true; Statements is the correct explanation for Statement I.

    Correct Answer: A

    Solution :

    We know that on an unbanked road the friction provides the necessary centripetal force which is \[\frac{m{{v}^{2}}}{r}=F=\mu R=\mu mg\] \[\Rightarrow \] \[v=\sqrt{\mu rg}\] This implies that with increase in friction, safe velocity increases. At banking angle of \[\theta \], its limiting velocity is given by \[v=\sqrt{\frac{rg(\mu +\tan \theta )}{(1-\mu \tan \theta )}}\] Thus, with increase of banking angle, limiting velocity increases.


You need to login to perform this action.
You will be redirected in 3 sec spinner