2046
Q1
Advance
1. SINGLE CORRECT CHOICE TYPE QUESTIONS
MCQ
A chain consisting of 5 links each of mass $0.1\mathrm{kg}$ is lifted vertically with a constant acceleration of $2.5\mathrm{ms}^{-2}$ . The force of interaction between the top link and the link immediately below it, will be
A.
$6.15\mathrm{N}$
B.
$4.92\mathrm{N}$
C.
$3.69\mathrm{N}$
D.
$2046\mathrm{N}$
Online April 2019
Q2
Advance
7. ARCHIVE: JEE MAIN
MCQ
If $10^{22}$ gas molecules each of mass $10^{-26}$ kg collide with a surface (perpendicular to it) elastically per second over an area $1\mathrm{m}^2$ with a speed $10^{4}\mathrm{ms}^{-1}$ , the pressure exerted by the gas molecules will be of the order of
A.
$1\mathrm{Nm}^{-2}$
B.
$2\mathrm{Nm}^{-2}$
C.
$3\mathrm{Nm}^{-2}$
D.
$4\mathrm{Nm}^{-2}$
Online April 2019
Q3
Advance
7. ARCHIVE: JEE MAIN
MCQ
A ball is thrown vertically up (taken as +z-axis) from the ground. The correct momentum height $(p-h)$ diagram is
A.
B.
C.
D.
Online April 2019
Q4
Advance
7. ARCHIVE: JEE MAIN
MCQ
A ball is thrown upward with an initial velocity $V_{0}$ from the surface of the earth. The motion of the ball is affected by a drag force equal to $m\gamma v^{2}$ (where m is mass of the ball, v is its instantaneous velocity and $\gamma$ is a constant). Time taken by the ball to rise to its zenith is
A.
$\frac{1}{\sqrt{\gamma g}}\sin^{-1}\left(\sqrt{\frac{\gamma}{g}} V_0\right)$
B.
$\frac{1}{\sqrt{\gamma g}}\ln \left(1 + \sqrt{\frac{\gamma}{g}} V_0\right)$
C.
$\frac{1}{\sqrt{\gamma g}}\tan^{-1}\left(\sqrt{\frac{\gamma}{g}}V_{0}\right)$
D.
$\frac{1}{\sqrt{2\gamma g}}\tan^{-1}\left(\sqrt{\frac{2\gamma}{g}} V_0\right)$
Online April 2019
Q5
Advance
7. ARCHIVE: JEE MAIN
MCQ
Two blocks A and B of masses $m_{A}=1$ kg and $m_{B}=3$ kg are kept on the table as shown in figure. The coefficient of friction between A and B is 0.2 and between B and the surface of the table is also 0.2. The maximum force F that can be applied on B horizontally, so that the block A does not slide over the block B is [Take $g=10\ ms^{-2}$ ]
A.
40 N
B.
12N
C.
16 N
D.
8 N
Online April 2019
Q6
Advance
7. ARCHIVE: JEE MAIN
MCQ
[Online April 2019] A block of mass 5 is kg (i) pushed in case (A) and (ii) pulled in case (B), by a force $F = 20 \, \text{N}$ , making an angle of $30^\circ$ with the horizontal, as shown in the figures. The coefficient of friction between the block and floor is $\mu = 0.2$ . The difference between the accelerations of the block, in case (B) and case (A) will be $(g = 10 \, \text{ms}^{-2})$
A.
C.
$0 \, ms^{-2}$
D.
$0.8 \, ms^{-2}$
Online April 2019
Q7
Advance
7. ARCHIVE: JEE MAIN
MCQ
A spring whose unstretched length is $l$ has a force constant $k$ . The spring is cut into two pieces of unstretched lengths $l_{1}$ and $l_{2}$ where, $l_{1} = nl_{2}$ and $n$ is an integer. The ratio $\frac{k_1}{k_2}$ of the corresponding force constants, $k_{1}$ and $k_{2}$ will be
A.
$n^2$
B.
$\frac{1}{n^2}$
C.
$n$
D.
$\frac{1}{n}$
Online April 2019
Q8
Advance
7. ARCHIVE: JEE MAIN
MCQ
A smooth wire of length $2\pi r$ is bent into a circle and kept in a vertical plane. A bead can slide smoothly on the wire. When the circle is rotating with angular speed $\omega$ about the vertical diameter AB, as shown in figure, the bead is at rest with respect to the circular ring at position P as shown. Then the value of $\omega^{2}$ is equal to
A.
$\frac{(g\sqrt{3})}{r}$
B.
$\frac{2g}{r}$
C.
$\frac{2g}{(r\sqrt{3})}$
D.
$\frac{\sqrt{3}g}{2r}$
Online January 2019
Q9
Advance
7. ARCHIVE: JEE MAIN
MCQ
A block of mass 10 kg is kept on a rough inclined plane as shown in the figure. A force of 3 N is applied on the block. The coefficient of static friction between the plane and the block is 0.6. What should be the minimum value of force P, such that the block does not move downward? (Take $g = 10 \, ms^{-2}$ )
A.
25 N
B.
32 N
C.
18 N
D.
23 N
Online January 2019
Q10
Advance
7. ARCHIVE: JEE MAIN
MCQ
A mass of $10\mathrm{kg}$ is suspended vertically by a rope from the roof. When a horizontal force is applied on the roof at some point, the rope deviated at an angle of $45^{\circ}$ at the roof point. If the suspended mass is at equilibrium, the magnitude of the force applied is $(g = 10\mathrm{ms}^{-2})$
A.
$100\mathrm{N}$
B.
$200\mathrm{N}$
C.
$70\mathrm{N}$
D.
$140\mathrm{N}$
Online January 2019
Q11
Advance
7. ARCHIVE: JEE MAIN
MCQ
A particle of mass m is moving in a straight line with momentum p. Starting at time t = 0, a force F = kt acts in the same direction on the moving particle during time interval T so that its momentum changes from p to 3p. Here k is a constant. The value of T is
A.
$\sqrt{\frac{2k}{p}}$
B.
$2\sqrt{\frac{p}{k}}$
C.
$\sqrt{\frac{2p}{k}}$
D.
$2\sqrt{\frac{k}{p}}$
Online January 2019
Q12
Advance
7. ARCHIVE: JEE MAIN
MCQ
A particle moves from the point $(2.0\hat{i}+4.0\hat{j})$ m, at t=0, with an initial velocity $(5.0\hat{i}+4.0\hat{j})$ ms $^{-1}$ . It is acted upon by a constant force which produces a constant acceleration $(4.0\hat{i}+4.0\hat{j})$ ms $^{-2}$ . What is the distance of the particle from the origin at time 2 s?
A.
$20\sqrt{2}$ m
B.
15 m
C.
$10\sqrt{2}$ m
D.
5 m
Online January 2019
Q13
Advance
7. ARCHIVE: JEE MAIN
MCQ
A block kept on a rough inclined plane, as shown in the figure, remains at rest up to a maximum force $2\mathrm{N}$ down the inclined plane. The maximum external force up the inclined plane that does not move the block is $10\mathrm{N}$ . The coefficient of static friction between the block and the plane is [Take $g = 10~\mathrm{ms}^{-2}$ ]
A.
$\frac{1}{2}$
B.
$\frac{\sqrt{3}}{2}$
C.
$\frac{\sqrt{3}}{4}$
D.
$\frac{2}{3}$
2018
Q14
Advance
7. ARCHIVE: JEE MAIN
MCQ
Two masses $m_{1}=5$ kg and $m_{2}=10$ kg, connected by an inextensible string over a frictionless pulley, are moving as shown in the figure.
The coefficient of friction of horizontal surface is 0.15. The minimum weight $m$ that should be put on top of $m_2$ to stop the motion is
The coefficient of friction of horizontal surface is 0.15. The minimum weight $m$ that should be put on top of $m_2$ to stop the motion is
A.
$18.3\mathrm{kg}$
B.
$27.3\mathrm{kg}$
C.
$43.3\mathrm{kg}$
D.
$10.3\mathrm{kg}$
Online 2018
Q15
Advance
7. ARCHIVE: JEE MAIN
MCQ
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
A.
$\sqrt{1-\frac{1}{n^{2}}}$
B.
$1-\frac{1}{n^{2}}$
C.
$\frac{1}{2-n^{2}}$
D.
$\sqrt{\frac{1}{1-n^{2}}}$
Online 2018
Q16
Advance
7. ARCHIVE: JEE MAIN
MCQ
A body of mass 2 kg slides down with an acceleration of $3 \, ms^{-2}$ on a rough inclined plane having a slope of $30^{\circ}$ . The external force required to take the same body up the plane with the same acceleration will be $(g = 10 \, \text{ms}^{-2})$
A.
6 N
B.
14 N
C.
4 N
D.
20 N
JEE (Advanced) 2018
Q17
Advance
8. ARCHIVE: JEE ADVANCED
Numerical
A solid horizontal surface is covered with a thin layer of oil. A rectangular block of mass $m = 0.4 \, \mathrm{kg}$ is at rest on this surface. An impulse of 1 Ns is applied to the block at time $t = 0$ , so that it starts moving along the X-axis with a velocity $v(t) = v_0 e^{-t / \tau}$ , where $v_0$ is a constant and $\tau = 4 \, \mathrm{s}$ . The displacement of the block, in metres, at $t = \tau$ is ...... (Take, $e^{-1} = 0.37$ ) [Round off your answer to nearest integer].
Correct Answer: 6
Explanation:
Linear impulse, $J = mv_{0}$
$\Rightarrow v _ {0} = \frac {J}{m} = 2. 5 \mathrm{ms} ^ {- 1}$
$\Rightarrow v = v _ {0} e ^ {- t / \tau}$
$\Rightarrow \frac {d x}{d t} = v _ {0} e ^ {- t / \tau}$
$\Rightarrow \int_ {0} ^ {x} d x = v _ {0} \int_ {0} ^ {\tau} e ^ {- t / \tau} d t$
$\Rightarrow x = v _ {0} \left[ \frac {e ^ {- t / \tau}}{- 1 / \tau} \right] _ {0} ^ {\tau}$
$\Rightarrow x = 2. 5 (- 4) \big (e ^ {- 1} - e ^ {0} \big)$
$\Rightarrow x = 2. 5 (- 4) (0. 3 7 - 1)$
$\Rightarrow x = 6. 3 0 \mathrm{m}$
$\Rightarrow x = 6 \mathrm{m}$
$\Rightarrow v _ {0} = \frac {J}{m} = 2. 5 \mathrm{ms} ^ {- 1}$
$\Rightarrow v = v _ {0} e ^ {- t / \tau}$
$\Rightarrow \frac {d x}{d t} = v _ {0} e ^ {- t / \tau}$
$\Rightarrow \int_ {0} ^ {x} d x = v _ {0} \int_ {0} ^ {\tau} e ^ {- t / \tau} d t$
$\Rightarrow x = v _ {0} \left[ \frac {e ^ {- t / \tau}}{- 1 / \tau} \right] _ {0} ^ {\tau}$
$\Rightarrow x = 2. 5 (- 4) \big (e ^ {- 1} - e ^ {0} \big)$
$\Rightarrow x = 2. 5 (- 4) (0. 3 7 - 1)$
$\Rightarrow x = 6. 3 0 \mathrm{m}$
$\Rightarrow x = 6 \mathrm{m}$
Online 2017
Q18
Advance
7. ARCHIVE: JEE MAIN
MCQ
Two particles $A$ and $B$ of equal mass $M$ are moving with the same speed $v$ as shown in the figure. They collide completely inelastically and move as a single particle $C$ . The angle $\theta$ that the path, $C$ makes with the X-axis is given by
A.
$\tan\theta=\frac{\sqrt{3}+\sqrt{2}}{1-\sqrt{2}}$
B.
$\tan\theta=\frac{1-\sqrt{3}}{1+\sqrt{2}}$
C.
$\tan\theta=\frac{\sqrt{3}-\sqrt{2}}{1-\sqrt{2}}$
D.
$\tan\theta=\frac{1-\sqrt{2}}{\sqrt{2}(1+\sqrt{3})}$
Online 2017
Q19
Advance
7. ARCHIVE: JEE MAIN
MCQ
A conical pendulum of length 1 m makes an angle $\theta = 45^{\circ}$ w.r.t. Z-axis and moves in a circle in the XY plane. The radius of the circle is 0.4 m and its center is vertically below O. The speed of the pendulum, in its circular path, will be (Take $g = 10 \, ms^{-2}$ )
A.
$0.4\mathrm{ms}^{-1}$
B.
$2\mathrm{ms}^{-1}$
C.
$0.2\mathrm{ms}^{-1}$
D.
$4\mathrm{ms}^{-1}$
Online 2016
Q20
Advance
7. ARCHIVE: JEE MAIN
MCQ
A rocket is fired vertically from the earth with an acceleration of 2g, where g is the gravitational acceleration. On an inclined plane inside the rocket, making an angle $\theta$ with the horizontal, a point object of mass m is kept. The minimum coefficient of friction $\mu_{min}$ between the mass and the inclined surface such that the mass does not move is
A.
$\tan2\theta$
B.
$\tan\theta$
C.
$3\tan\theta$
D.
$2\tan\theta$
Online 2016
Q21
Advance
7. ARCHIVE: JEE MAIN
MCQ
A particle of mass m is acted upon by a force F given by the empirical law $F = \frac{R}{t^{2}} v(t)$ . If this law is to be tested experimentally by observing the motion starting from rest, the best way is to plot
(A) $\log v(t)$ against $\frac{1}{t}$
A.
$\log v(t)$ against $\frac{1}{t}$
B.
$v(t)$ against $t^{2}$
C.
$\log v(t)$ against $\frac{1}{t^{2}}$
D.
$\log v(t)$ against t
JEE (Advanced) 2016
Q22
Advance
8. ARCHIVE: JEE ADVANCED
MCQ
A uniform wooden stick of mass 1.6 kg and length l rests in an inclined manner on a smooth, vertical wall of height $h(
A.
$\frac {h}{l} = \frac {\sqrt {3}}{1 6}, f = \frac {1 6 \sqrt {3}}{3} \mathrm{N}$
B.
$\frac {h}{l} = \frac {3}{1 6}, f = \frac {1 6 \sqrt {3}}{3} \mathrm{N}$
C.
$\frac{h}{l}=\frac{3\sqrt{3}}{16},\quad f=\frac{8\sqrt{3}}{3},\text{N}$
D.
$\frac{h}{l}=\frac{3\sqrt{3}}{16},\quad f=\frac{16\sqrt{3}}{3},\text{N}$
2015
Q23
Advance
7. ARCHIVE: JEE MAIN
MCQ
Given in the figure are two blocks $A$ and $B$ of weight $20\mathrm{N}$ and $100\mathrm{N}$ , respectively. These are being pressed against a wall by a force $F$ as shown. If the coefficient of friction between the blocks is 0.1 and between block $B$ and the wall is 0.15, the frictional force applied by the wall on block $B$ is
A.
$120\mathrm{N}$
B.
$150\mathrm{N}$
C.
$100\mathrm{N}$
D.
$80\mathrm{N}$
Online 2015
Q24
Advance
7. ARCHIVE: JEE MAIN
MCQ
A block of mass m = 10 kg rests on a horizontal table. The coefficient of friction between the block and the table is 0.05. When hit by a bullet of mass 50 g moving with speed v, that gets embedded in it, the block moves and comes to stop after moving a distance of 2 m on the table. If a freely falling object were to acquire speed $\frac{v}{10}$ after being dropped from height H, then neglecting energy losses and taking $g = 10 \, ms^{-2}$ , the value of H is close to
A.
0.2 km
B.
0.3 km
C.
0.04 km
D.
0.5 km
Online 2015
Q25
Advance
7. ARCHIVE: JEE MAIN
MCQ
A large number (n) of identical beads, each of mass m and radius r are strung on a thin smooth rigid horizontal rod of length $L(L \gg r)$ and are at rest at random positions. The rod is mounted between two rigid supports (shown in figure). If one of the beads is now given a speed v, the average force experienced by each support after a long time is (assume all collisions are elastic)
A.
$\frac{mv^2}{L - nr}$
B.
$\frac{mv^2}{L - 2nr}$
C.
$\frac{mv^2}{2(L - nr)}$
D.
zero












