Laws of Motion & Friction · JEE Main previous year questions

2018 3 questions

1. Q572018 · 16 Apr 2018 · Shift 1

   Two sitar strings, A and B, playing the note 'Dha' are slightly out of tune and produce beats of frequency 5 Hz. The tension of the string B s slightly increased and the beat frequency is found to decrease by 3Hz. If the frequency of A is 425 Hz, the original frequency of B is :

   1. A.430 Hz
   2. B.420 Hz
   3. C.428 Hz
   4. D.422 Hz
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   Answer: B

2. Q322018 · 15 Apr 2018 · Shift 1

   A given object takes n times more time to slide down a $45^{\circ }$ rough inclined plane as it takes to slide down a perfectly smooth $45^{\circ }$ incline. The coefficient of kinetic friction between the object and the incline is :

   1. A.$\frac{1}{2-n^2}$
   2. B.$1-\frac{1}{n^2}$
   3. C.$\sqrt{1-\frac{1}{n^2}}$
   4. D.$\sqrt{\frac{1}{1-n^2}}$
   Show answer

   Answer: B

3. Q332018 · 8 Apr 2018 · Shift 1
   
   1. A.$10.3\mathrm{kg}$
   2. B.$18.3\mathrm{kg}$
   3. C.$27.3\mathrm{kg}$
   4. D.$43.3\mathrm{kg}$
   Show answer

   Answer: C