Laws of Motion & Friction · JEE Main previous year questions

2014 3 questions

1. Q332014 · 6 Apr 2014 · Shift 1

   A block of mass $m$ is placed on a surface with a vertical cross section given by $y=\frac{x^3}{6}$. If the coefficient of friction is $0.5$, the maximum height above the ground at which the block can be placed without slipping is:

   1. A.$\frac{1}{6}\mathrm{m}$
   2. B.$\frac{2}{3}\mathrm{m}$
   3. C.$\frac{1}{3}\mathrm{m}$
   4. D.$\frac{1}{2}\mathrm{m}$
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   Answer: A

2. Q352014 · 6 Apr 2014 · Shift 1

   A bob of mass $m$ attached to an inextensible string of length $l$ is suspended from a vertical support. The bob rotates in a horizontal circle with an angular speed $\omega rad/s$ about the vertical. About the point of suspension:

   1. A.angular momentum is conserved
   2. B.angular momentum changes in magnitude but not in direction.
   3. C.angular momentum changes in direction but not in magnitude.
   4. D.angular momentum changes both in direction and magnitude.
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   Answer: C

3. Q382014 · 6 Apr 2014 · Shift 1
   
   1. A.$\frac{2g}{3}$
   2. B.$\frac{g}{2}$
   3. C.$\frac{5g}{6}$
   4. D.$g$
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   Answer: B