JEE Main Physics — Mechanics previous year questions with solutions.
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
Given below are two statements: Statement I: Acceleration due to earth's gravity decreases as you go 'up' or 'down' from earth's surface. Statement II: Acceleration due to earth's gravity is same at a height '$h$' and depth '$d$' from earth's surface, if $h=d$. In the light of above statements, choose the most appropriate answer form the options given below
Three forces ${F}_{1}=10N,{F}_{2}=8N,{F}_{3}=6N$ are acting on a particle of mass $5\mathrm{kg}$. The forces ${F}_{2}$ and ${F}_{3}$ are applied perpendicularly so that particle remains at rest. If the force ${F}_{1}$ is removed, then the acceleration of the particle is
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 $________.$
If two vectors $\vec{P}=\hat{i}+2m\hat{j}+m\hat{k}$ and $\vec{Q}=4\hat{i}-2\hat{j}+m\hat{k}$ are perpendicular to each other. Then, the value of $m$ will be
Force acts for $20s$ on a body of mass $20\mathrm{kg}$, starting from rest, after which the force ceases and then body describes $50m$ in the next $10s$. The value of force will be :
A force $\vec{F}=(2+3x)\hat{i}$ acts on a particle in the $x$ direction where $F$ is in Newton and $x$ is in meter. The work done by this force during a displacement from $x=0$ to $x=4m$ is _____ $J$.
If the earth suddenly shrinks to $\frac{1}{64}\mathrm{th}$ of its original volume with its mass remaining the same, the period of rotation of earth becomes $\frac{24}{x}h$. The value of $x$ is ________
A body weight $W$, is projected vertically upwards from earth's surface to reach a height above the earth which is equal to nine times the radius of earth. The weight of the body at that height will be:
$(P+\frac{a}{{V}^{2}})(V-b)=RT$ represents the equation of state of some gases. Where $P$ is the pressure, $V$ is the volume, $T$ is the temperature and $a,b,R$ are the constants. The physical quantity, which has dimensional formula as that of $\frac{{b}^{2}}{a}$ , will be :
Under the same load, wire A having length $5.0m$ and cross section $2.5\times {10}^{-5}{m}^{2}$ stretches uniformly by the same amount as another wire $B$ of length $6.0m$ and a cross section of $3.0\times {10}^{-5}{m}^{2}$ stretches. The ratio of the Young's modulus of wire $A$ to that of wire $B$ will be:
The escape velocities of two planets $AandB$ are in the ratio $1:2$. If the ratio of their radii respectively is $1:3$, then the ratio of acceleration due to gravity of planet $A$ to the acceleration of gravity of planet $B$ will be:
Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R.$ Assertion A: When a body is projected at an angle $45^{\circ},$ its range is maximum. Reason R: For maximum range, the value of sin $2\theta$ should be equal to one. In the light of the above statements, choose the correct answer from the options given below:
A solid sphere of mass $2\mathrm{kg}$ is making pure rolling on a horizontal surface with kinetic energy $2240J$. The velocity of centre of mass of the sphere will be ______ $m{s}^{-1}$.
A fully loaded boeing aircraft has a mass of $5.4\times {10}^{5}\mathrm{kg}$. Its total wing area is $500{m}^{2}$. It is in level flight with a speed of $1080\mathrm{km}{h}^{-1}$. If the density of air $\rho$ is $1.2\mathrm{kg}{m}^{–3}$, the fractional increase in the speed of the air on the upper surface of the wing relative to the lower surface in percentage will be ($g=10m{s}^{-2}$)
A ring and a solid sphere rotating about an axis passing through their centres have same radii of gyration. The axis of rotation is perpendicular to plane of ring. The ratio of radius of ring to that of sphere is $\sqrt{\frac{2}{x}}$. The value of $x$ is _____.
A body of mass $2\mathrm{kg}$ is initially at rest. It starts moving unidirectionally under the influence of a source of constant power $P$. Its displacement in $4s$ is $\frac{1}{3}{\alpha }^{2}\sqrt{P}m$. The value of $\alpha$ will be ______.
A steel rod has a radius of $20\mathrm{mm}$ and a length of $2.0m.$ A force of $62.8\mathrm{kN}$ stretches it along its length. Young's modulus of steel is $2.0\times {10}^{11}N{m}^{-2}$. The longitudinal strain produced in the wire is $_________\times {10}^{-5}$.
A horse rider covers half the distance with $5m{s}^{-1}$ speed. The remaining part of the distance was travelled with speed $10m{s}^{-1}$ for half the time and with speed $15m{s}^{-1}$ for other half of the time. The mean speed of the rider averaged over the whole time of motion is $\frac{x}{7}m{s}^{-1}$. The value of $x$ is ______.
In an experiment with vernier callipers of least count $0.1\mathrm{mm}$, when two jaws are joined together the zero of vernier scale lies right to the zero of the main scale and ${6}^{\mathrm{th}}$ division of vernier scale coincides with the main scale division. While measuring the diameter of a spherical bob, the zero of vernier scale lies in between $3.2\mathrm{cm}$ and $3.3\mathrm{cm}$ marks and ${4}^{\mathrm{th}}$ division of vernier scale coincides with the main scale division. The diameter of bob is measured as
A body of mass is taken from earth surface to the height $h$ equal to twice the radius of earth $({R}_{e})$, the increase in potential energy will be : ($g=$ acceleration due to gravity on the surface of earth)
If the velocity of light $c$, universal gravitational constant $G$ and planck's constant $h$ are chosen as fundamental quantities. The dimensions of mass in the new system is:
Three forces ${F}_{1}=10N,{F}_{2}=8N,{F}_{3}=6N$ are acting on a particle of mass $5\mathrm{kg}$. The forces ${F}_{2}$ and ${F}_{3}$ are applied perpendicularly so that particle remains at rest. If the force ${F}_{1}$ is removed, then the acceleration of the particle is
The range of the projectile projected at an angle of ${15}^{\circ }$ with horizontal is $50m$. If the projectile is projected with same velocity at an angle of ${45}^{\circ }$ with horizontal, then its range will be