Work, Energy & Power · JEE Main previous year questions

2004 5 questions

1. Q792004 · 24 Apr 2004 · Shift 1

   A uniform chain of length $2\mathrm{m}$ is kept on a table such that a length of $60\mathrm{cm}$ hangs freely from the edge of the table. The total mass of the chain is $4\mathrm{kg}$. What is the work done in pulling the entire chain on the table?

   1. A.$12\mathrm{J}$
   2. B.$3.6\mathrm{J}$
   3. C.$7.2\mathrm{J}$
   4. D.$1200\mathrm{J}$
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   Answer: B

2. Q802004 · 24 Apr 2004 · Shift 1

   A force $\vec{F}=(5\vec{i}+3\vec{j}+2\vec{k})\mathrm{N}$ is applied over a particle which displaces it from its origin to the point $\vec{r}=(2\vec{i}-\vec{j})\mathrm{m}$. The work done on the particle in joules is

   1. A.$+10$
   2. B.$+7$
   3. C.$-7$
   4. D.$+13$
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   Answer: B

3. Q812004 · 24 Apr 2004 · Shift 1

   A body of mass ${}^{\prime }{m}^{\prime }$, accelerates uniformly from rest to ${}^{\prime }{v}_1^{\prime }$ in time $T$. The instantaneous power delivered to the body as a function of time is given by

   1. A.$\frac{m{v}_1{t}^2}{T}$
   2. B.$\frac{m{v}_1^{2}t}{T^2}$
   3. C.$\frac{m{v}_{1}t}{T}$
   4. D.$\frac{m{v}_1^{2}t}{T}$
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   Answer: B

4. Q882004 · 24 Apr 2004 · Shift 1

   If $g$ is the acceleration due to gravity on the earth's surface, the gain in the potential energy of an object of mass $m$ raised from the surface of the earth to a height equal to the radius $R$ of the earth is

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

5. Q902004 · 24 Apr 2004 · Shift 1

   A wire fixed at the upper end stretches by length $l$ by applying a force $F$. The work done in stretching is

   1. A.$2Fl$
   2. B.$Fl$
   3. C.$\frac{F}{2l}$
   4. D.$\frac{Fl}{2}$
   Show answer

   Answer: D