JEE Main Physics — Mechanics previous year questions with solutions.
A smooth block is released at rest on a $45^{\circ}$ incline and then slides a distance d. The time taken to slide is $\mathrm{n}$ times as much to slide on rough incline than on a smooth incline. The coefficient of friction is
The upper half of an inclined plane with inclination $\phi$ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coefficient of friction for the lower half is given by
A machine gun fires a bullet of mass $40 \mathrm{~g}$ with a velocity $1200 \mathrm{~ms}^{-1}$. The man holding it can exert a maximum force of $144 \mathrm{~N}$ on the gun. How many bullets can he fire per second at the most?
If $t_1$ and $t_2$ are the times of flight of two particles having the same initial velocity $u$ and range $\mathrm{R}$ on the horizontal, then $\mathrm{t}_1^2+\mathrm{t}_2^2$ is equal to
If $\vec{A} \times \vec{B}=\vec{B} \times \vec{A}$, then the angle between $A$ and $B$ is
A wire fixed at the upper end stretches by length by applying a force F. The work done in stretching is
A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement $\mathrm{x}$ is proportional to
Which of the following statements is false for a particle moving in a circle with a constant angular speed?
A force $\vec{F}=(5 \hat{i}+3 \hat{j}+2 \hat{k}) N$ is applied over a particle which displaces it from its origin to the point $\vec{r}=(2 \hat{i}-\hat{j}) m$. The work done on the particle in joules is
A uniform chain of length $2 \mathrm{~m}$ is kept on a table such that a length of $60 \mathrm{~cm}$ hangs freely from the edge of the table. The total mass of the chain is $4 \mathrm{~kg}$. What is the work done in pulling the entire chain on the table?
If two soap bubbles of different radii are connected by a tube,
Spherical balls of radius $R$ are falling in a viscous fluid of viscosity $\eta$ with a velocity $v$. The retarding viscous force acting on the spherical ball is
A body of mass $m$, accelerates uniformly from rest to $v_1$ in time $t_1$. The instantaneous power delivered to the body as a function of time $t$ is
A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle, the motion of the particle takes place in a plane. It follows that
The time period of an earth satellite in circular orbit is independent of
Suppose the gravitational force varies inversely as the nth power of distance. Then the time period planet in circular orbit of radius $\mathrm{R}$ around the sun will be proportional to
One solid sphere A and another hollow sphere B are of same mass and same outer radii. Their moment of inertia about their diameters are respectively $\mathrm{I}_{\mathrm{A}}$ and $\mathrm{I}_{\mathrm{B}}$ such that
A block rests on a rough inclined plane making an angle of $30^{\circ}$ with the horizontal. The coefficient of static friction between the block and the plane is $0.8$. If the frictional force on the block is $10 \mathrm{~N}$, the mass of the block (in $\mathrm{kg}$ ) is (take $\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$ )
Which one of the following represents the correct dimensions of the coefficient of viscosity?
A ball is released from the top of a tower of height $h$ metres. It takes $T$ seconds to reach the ground. What is the position of the ball in $\mathrm{T} / 3$ seconds?
Two masses $m_1=5 \mathrm{~kg}$ and $m_2=4.8 \mathrm{~kg}$ tied to a string are hanging over a light frictionless pulley. What is the acceleration of the masses when lift free to move $\left(\mathrm{g}=9.8 \mathrm{~m} / \mathrm{s}^2\right)$ 
A ball is thrown from a point with a speed $v_0$ at an angle of projection $\theta$. From the same point and at the same instant person starts running with a constant speed $v_0 / 2$ to catch the ball. Will the person be able to catch the ball? If yes, what should be the angle of projection?
A solid sphere is rotating in free space. If the radius of the sphere is increased keeping mass same which one of the following will not be affected?
A projectile can have the same range $R$ for two angles of projection. If $T_1$ and $T_2$ be the time of flights in the two cases, then the product of the two time of flights is directly proportional to