Question 1 :
<font>In an ice rink a skator is moving at 3 ms</font>^{<font>-1</font>}<font> and encounters a rough patch that reduces her speed by 45% due to a friction force that is 25% of her weight. Find the length of the rough patch</font></p>

Question 2 :
<font>A person pushes a block of mass 4 kg up a frictionless inclined plane 10 m long and that makes an angle of 30° with the horizontal. Then the work done is -</font></p>

Question 3 :
<font>A proton has a positive charge. If two protons are brought near to one another, the potential energy of the system will</font></p>

Question 5 :
<font>Similar of cubical shape of edge b are lying on ground. Density of material of slab is </font><font face="Symbol, serif"><font></font></font><font>. Work done to arrange then one over the other is </font> </p> <p align="center"> <img style='object-fit:contain' align="bottom" height="147" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5fc0f59ae6377b2e815f593c" width="61"/> </p>

Question 6 :
<font>A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. In which direction will it move?</font></p> <p align="justify"> <font color="#000000">

Question 7 :
A particle charge q and mass m is projected with a velocity {tex}v_{0}{/tex} towards a circular region having uniform magnetic field B perpendicular and into the plane of paper from point P as shown in Fig. 15.56. R is the radius and O is the centre of the circular region. If the line OP makes an angle {tex}\theta{/tex} with the direction of {tex}v_{0}{/tex} then the value of {tex}v_{0}{/tex} so that particle passes through O is <br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5d5abf215637834a58898650" /><br>

Question 8 :
<font>A bar magnet of dipole moment 10</font>^{<font>4</font>}<font> JT</font>^{<font>-1</font>}<font> is free to rotate in a horizontal plane. A horizontal magnetic field 4 × 10</font>^{<font>-5</font>}<font> T exists in the space. Find the work done in rotating the magnet slowly from a direction parallel to the field to a direction 60</font>^{<font>0</font>}<font> from the field -</font></p>

Question 9 :
An electron has mass $9 \times 10^{-31}kg$ and charge $1.6 \times 10^{-19} C$ is moving with a velocity if $10^{6} m/s,$ enters a region where magnetic field exists. If it describes a circle of radius $0.10m$, the intensity of magnetic field must be:

Question 10 :
A solenoid of {tex} 1.5 \ metre {/tex} length and {tex} 4.0 \ cm {/tex} diameter posses {tex}10{/tex} turn per {tex} c m . {/tex} A current of {tex}5\ ampere{/tex} is flowing through it. The magnetic induction at axis inside the solenoid is