Collision & Variable Mass: JEE Main Physics Previous Year Questions

119 previous year questions from Collision & Variable Mass. Here are the 25 most important ones; open any question for the correct answer and a full step-by-step solution.

1. 1.When two bodies collide elastically, then
2. 2.A ball is thrown vertically downwards from a height of 20 m with an initial velocity $v_0$. It collides with the ground, loses $50\text{\%}$ of its energy in collis…
3. 3.A machine gun of mass 10 kg fires 20 g bullets at the rate of 180 bullets per minute with a speed of 100 m $s^{-1}$ each. The recoil velocity of the gun is:
4. 4.A moving particle collides with a stationary particle of mass $\frac{1}{n}$ times the mass of moving particle, the fraction of its kinetic energy transferred to the stat…
5. 5.Two particles $A$ and $B$, move with constant velocities $v_1$ and $v_2$. At the initial moment their position vectors are $r_1$ and $r_2$ respectiv…
6. 6.Two bodies of mass $1\text{kg}$ and $3\text{kg}$ have position vectors $i+2j+k$ and $-3i-2j+k$, respectively. The centre of mass of this system has a position vector:
7. 7.A block of mass 10 kg starts sliding on a surface with an initial velocity of 9.8 $m{s}^{-1}$. The coefficient of friction between the surface and bock is 0.5. The distance…
8. 8.A $1\text{kg}$ ball moving at $12m{s}^{-1}$ collides with a $2\text{kg}$ ball moving in opposite direction at $24m{s}^{-1}$.…
9. 9.A ball is dropped from some height and after first collision with the ground if it reaches ${\frac{3}{4}}^{\text{th}}$ of its original height, then the $\text{\%}$ loss…
10. 10.A wedge of mass $M=4m$ lies on a frictionless plane. A particle of mass $m$ approaches the wedge with speed $v$. There is no friction between the particle and the plan…
11. 11.Two particles of masses $m_1\text{,}{m}_2$ move with initial velocities $u_1$ and $u_2$. On collision, one of the particles get excited to higher level,…
12. 12.A body falls freely from a height of $100m$ on to the ground and rebounds to a maximum height of $36m$ after collision. The coefficient of restitution bet…
13. 13.A ball hits the floor and rebounds after an inelastic collision. In this case
14. 14.The coefficient of restitution $e$ for a perfectly elastic collision is
15. 15.A body of mass M at rest explodes into three pieces, in the ratio of masses 1:1:2. Two smaller pieces fly off perpendicular to each other with velocities of 30 $m{s}^{-1}$…
16. 16.A spaceship in space sweeps stationary interplanetary dust. As a result, its mass increases at a rate…
17. 17.A body of mass 2 kg makes an elastic collision with a second body at rest and continues to move in the original direction but with one fourth of its original speed. What…
18. 18.A moving block having mass m, collides with another stationary block having mass 4 m. The lighter block comes to rest after collision. When the initial velocity of the li…
19. 19.A body $A$, of mass $m=0.1\text{kg}$ has an initial velocity of $3\hat{i}m{s}^{-1}$. It collides elastically with another body, $B$ of the same mass which has an init…
20. 20.If the total energy transferred to a surface in time $t$ is $6.48\times {10}^{5}J$, then the magnitude of the total momentum delivered to this surface for comple…
21. 21.Statement-1 : Two particles moving in the same direction do not lose all their energy in a completely inelastic collision. Statement-2 : Principle of conservation of mome…
22. 22.Collision takes place between two solid spheres denoted as 1 and 2. The initial velocities of the sphere are $u_1=3m/s$ and $u_2=1.5m/s$ and the f…
23. 23.A particle of mass $m$ is dropped from a height $h$ above the ground. At the same time another particle of the same mass is thrown vertically upwards from the ground wi…
24. 24.A bullet of mass 0.1 kg moving horizontally with speed 400 m $s^{-1}$ hits a wooden block of mass 3. 9 kg kept on a horizontal rough surface. The bullet gets embedded int…
25. 25.A moving body of mass $m$ and velocity 3 km/hour collides with a rest body of mass $2m$ and sticks to it. Now the combined mass starts to move. What will be the combine…