JEE Main Physics — Mechanics previous year questions with solutions.
A physical quantity $P$ is given as $P=\frac{{a}^{2}{b}^{3}}{c\sqrt{d}}$. The percentage error in the measurement of $a,b,c$ and $d$ are $1%,2%,3%$ and $4%$ respectively. The percentage error in the measurement of quantity $P$ will be
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : A spherical body of radius $(5\pm 0.1)\mathrm{mm}$ having a particular density is falling through a liquid of constant density. The percentage error in the calculation of its terminal velocity is $4%$. Reason R : The terminal velocity of the spherical body falling through the liquid is inversely proportional to its radius. In the light of the above statements, choose the correct answer from the options given below
Vectors $a\hat{i}+b\hat{j}+\hat{k}$ and $2\hat{i}-3\hat{j}+4\hat{k}$ are perpendicular to each other when $3a+2b=7$, the ratio of $a$ to $b$ is $\frac{x}{2}$. The value of $x$ is _____.
A solid sphere of mass $500g$ radius $5\mathrm{cm}$ is rotated about one of its diameter with angular speed of $10\mathrm{rad}{s}^{-1}$. If the moment of inertia of the sphere about its tangent is $x\times {10}^{-2}$ times its angular momentum about the diameter. Then the value of $x$ will be
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion (A) : Steel is used in the construction of buildings and bridges. Reason (R) : Steel is more elastic and its elastic limit is high. In the light of above statements, choose the most appropriate answer from the options given below
Figures (a), (b), (c) and (d) show variation of force with time.  The impulse is highest in figure.
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : An electric fan continues to rotate for some time after the current is switched off. Reason R: Fan continues to rotate due to inertia of motion. In the light of above statements, choose the most appropriate answer from the options given below.
Two satellites $A$ and $B$ move round the earth in the same orbit. The mass of $A$ is twice the mass of $B$. The quantity which is same for the two satellites will be
If the distance of the earth from Sun is $1.5\times {10}^{6}\mathrm{km}$, then the distance of an imaginary planet from Sun, if its period of revolution is $2.83$ years is:
A small particle of mass $m$ moves in such a way that its potential energy $U=\frac{1}{2}m{\omega }^{2}{r}^{2}$ where $\omega$ is constant and $r$ is the distance of the particle from origin. Assuming Bohr’s quantization of momentum and circular orbit, the radius of ${n}^{\mathrm{th}}$ orbit will be proportional to
A particle of mass $10g$moves in a straight line with retardation $2x,$ where $x$ is the displacement in $\mathrm{SI}$ units. Its loss of kinetic energy for above displacement is ${(\frac{10}{x})}^{-n}J.$ The value of $n$ will be $________.$
The length of a metallic wire is increased by $20%$ and its area of cross-section is reduced by $4%.$ The percentage change in resistance of the metallic wire is $________.$
The figure represents the momentum time $(p-t)$ curve for a particle moving along an axis under the influence of the force. Identify the regions on the graph where the magnitude of the force is maximum and minimum respectively ? If $({t}_{3}-{t}_{2})<{t}_{1}$ 
Two forces having magnitude $A$ and $\frac{A}{2}$ are perpendicular to each other. The magnitude of their resultant is:
A solid sphere and a solid cylinder of same mass and radius are rolling on a horizontal surface without slipping. The ratio of their radius of gyrations respectively $({k}_{sph}:{k}_{cyl})$ is $2:\sqrt{x}$. The value of $x$ is _______.
A mass $m$ is attached to two springs as shown in figure. The spring constants of two springs are ${K}_{1}$ and ${K}_{2}.$ For the frictionless surface, the time period of oscillation of mass $m$ is 
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion $A$: A pendulum clock when taken to Mount Everest becomes fast. Reason $R$: The value of g (acceleration due to gravity) is less at Mount Everest than its value on the surface of earth. In the light of the above statements, choose the most appropriate answer from the options given below
A nucleus disintegrates into two smaller parts, which have their velocities in the ratio $3:2$. The ratio of their nuclear sizes will be ${(\frac{x}{3})}^{\frac{1}{3}}$. The value of ‘$x$’ is:
The acceleration due to gravity at height $h$ above the earth if $h\ll R$ (Radius of earth) is given by
Two forces having magnitude $A$ and $\frac{A}{2}$ are perpendicular to each other. The magnitude of their resultant is:
Two resistance are given as ${R}_{1}=(10\pm 0.5)\Omega$ and ${R}_{2}=(15\pm 0.5)\Omega .$ The percentage error in the measurement of equivalent resistance when they are connected in parallel is
The length of a wire becomes ${l}_{1}$ and ${l}_{2}$ when $100N$ and $120N$ tension are applied respectively. If $10{l}_{2}=11{l}_{1}$, then the natural length of wire will be $\frac{1}{x}{l}_{1}$. Here the value of $x$ is
An aluminium rod with Young’s modulus $Y=7.0\times {10}^{10}N{m}^{-2}$ undergoes elastic strain of $0.04%$. The energy per unit volume stored in the rod in $\mathrm{SI}$ unit
As shown in the figure, in an experiment to determine Young's modulus of a wire, the extension-load curve is plotted. The curve is a straight line passing through the origin and makes an angle of $45^{\circ}$ with the load axis. The length of wire is $62.8\mathrm{cm}$ and its diameter is $4\mathrm{mm}$. The Young's modulus is found to be $x\times {10}^{4}N{m}^{-2}$ The value of $x$ is _______. 