JEE Main Physics — Mechanics previous year questions with solutions.
A man grows into a giant such that his linear dimensions increase by a factor of $9.$ Assuming that his density remains same, the stress in the leg will change by a factor of:
The moment of inertia of a uniform cylinder of length $l$ and radius $R$ about its perpendicular bisector is $I.$ What is the ratio $l/R$ such that the moment of inertia is minimum?
If the Earth has no rotational motion, the weight of a person on the equator is $W$. Determine the speed with which the earth would have to rotate about its axis so that the person at the equator will weigh $\frac{3}{4} W$. The radius of the Earth is $6400\mathrm{km}$ and $g=10 m{s}^{-2}$
The machine as shown has $2$ rods of length $1m$ connected by a pivot at the top. The end of one rod is connected to the floor by a stationary pivot and the end of the other rod has roller that rolls along the floor in a slot. As the roller goes back and forth, a $2\mathrm{kg}$ weight moves up and down. If the roller is moving towards right at a constant speed, the weight moves up with a : 
A time dependent force $F=6t$ acts on a particle of mass $1\mathrm{kg}$. If the particle starts from the rest, the work done by the force during the first $1\mathrm{sec}$ will be:
The following observations were taken for determining surface tension $T$ of water by capillary method: diameter of capillary, $D=1.25\times {10}^{-2}m$ rise of water, $h=1.45\times {10}^{-2}m$ Using $g=9.80 m{s}^{-2}$ and the simplified relation $T=\frac{rhg}{2}\times {10}^{3}N{m}^{-1}$ the possible error in surface tension is closest to:
The variation of acceleration due to gravity $g$ with distance $d$ from the centre of the earth is best represented by ($R$= Earth's radius):
A body of mass $m={10}^{-2}\mathrm{kg}$ is moving in a medium and experiences a frictional force $F=-k{v}^{2} .$ Its initial speed is ${v}_{0}=10m{s}^{-1}.$ After $10s$ its kinetic energy is $\frac{1}{8}m{v}_{0}^{2},$ then value of $k$ will be:-
A body is thrown vertically upwards. Which one of the following graphs correctly represents the velocity$(v)$ vs time $(t)$?
A car is standing $200 m$ behind a bus, which is also at rest. The two start moving at the same instant but with different forward accelerations. The bus has acceleration $2m{s}^{-2}$ and the car has acceleration $4 m{s}^{-2}$ . The car will catch up with the bus after time :
The mass density of a spherical body is given by $\rho (r)=\frac{k}{r}$ for $r\leq R$ and $\rho (r)=0$ for $r>R,$ where $r$ is the distance from the center. The correct graph that describes qualitatively the acceleration, $a$ of a test particle as a function of $r$ is:
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 cubical block of side $30\mathrm{cm}$ is moving with velocity $2m{s}^{-1}$ on a smooth horizontal surface. The surface has a bump at a point $O$ as shown in the figure. The angular velocity (in rad/s) of the block immediately after it hits the bump, is : 
$A, B, C$, and $D$ are four different physical quantities having different dimensions. None of them is dimensionless. But we know that the equation $AD=C ln( BD )$ holds true. Then which of the combination is not a meaningful quantity?
A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1m 1000 times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will he use up considering the work done only when the weight is lifted up? Fat supplies $3.8\times {10}^{7}$ J of energy per kg which is converted to mechanical energy with a 20% efficiency rate. Take $g=9.8 m{s}^{-2}$ :
In the following $I$ refers to current and other symbols have their usual meaning. Choose the option that corresponds to the dimensions of electrical conductivity:
Which of the following option correctly describes the variation of the speed $\upsilon$ and acceleration 'a' of a point mass falling vertically in a viscous medium that applies a force $F=-k\upsilon$ , where 'k' is a constant, on the body? (Graphs are schematic and not drown to scale)
A point particle of mass m, moves along the uniformly rough track PQR as shown in the figure. The coefficient of friction, between the particle and the rough track equals $\mu$ . The particle is released, from rest, from the point P and it comes to rest at a point R. The energies, lost by the ball, over the parts, PQ and QR, of the track, are equal to each other, and no energy is lost when particle changes direction from PQ to QR. The values of the coefficient of friction $\mu$ and the distance $x=(QR)$ , are respectively close to: 
A particle of mass m is moving along the side of a square of side 'a', with a uniform speed $\upsilon$ in the x-y plane as shown in the figure:  Which of the following statements is false for the angular momentum $\vec{L}$ about the origin?
A roller is made by joining together two cones at their vertices O. It is kept on two rails AB and CD which are placed asymmetrically (see figure), with its axis perpendicular to CD and its centre O at the centre of line joining AB and CD (see figure). It is given a light push so that it starts rolling with its centre O moving parallel to CD in the direction shown. As it moves, the roller will tend to: 
The velocity-time graph of a particle of mass $10\mathrm{kg}$ is shown in the figure. The net work done on the particle in the first two seconds of the motion is 
A thin $1m$ long rod has a radius of $5\mathrm{mm}$. A force of $50{\text{π×10}}^{3}N$ is applied at one end to determine its Young's modulus. Assume that the force is exactly known. If the least count in the measurement of all lengths is $0.01\mathrm{mm}$, which of the following statements is false?
A satellite is revolving in a circular orbit at a height $h$ from the earth's surface (radius of earth $R$; $\text{h} \text{<<} \text{R}$ ). The minimum increase in its orbital velocity required, so that the satellite could escape from the earth's gravitational field, is close to (Neglect the effect of atmosphere.)
In the figure shown $ABC$ is a uniform wire. If the center of mass of the wire lies vertically below point $A$, then $\frac{BC}{AB}$ is close to 