A particle of mass $m$ is moving along the $x$ -axis with initial velocity $u \hat i$. It collides elastically with a particle of mass $10\, m$ at rest and then moves with half its initial kinetic energy (see figure). If $\sin \theta_{1}=\sqrt{n} \sin \theta_{2}$ then value of $n$ is.....

981-23

  • [JEE MAIN 2020]
  • A

    $20$

  • B

    $26$

  • C

    $10$

  • D

    $15$

Similar Questions

A steel ball of radius $2\, cm$ is at rest on a frictionless surface. Another ball of radius $4\,cm$ moving at a velocity of $81 \,cm/sec$ collides elastically with first ball. After collision the smaller ball moves with speed of ............. $\mathrm{cm} / \mathrm{sec}$

A point mass of $1 \mathrm{~kg}$ collides elastically with a stationary point mass of $5 \mathrm{~kg}$. After their collision, the $1 \mathrm{~kg}$ mass reverses its direction and moves with a speed of $2 \mathrm{~ms}^{-1}$. Which of the following statement(s) is (are) correct for the system of these two masses?

$(A)$ Total momentum of the system is $3 \mathrm{~kg} \mathrm{~ms}^{-1}$

$(B)$ Momentum of $5 \mathrm{~kg}$ mass after collision is $4 \mathrm{~kg} \mathrm{~ms}^{-1}$

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$(D)$ Total kinetic energy of the system is $4 \mathrm{~J}$

  • [IIT 2010]

Three objects $A, B$ and $C$ are kept in a straight line on a frictionless horizontal surface. The masses of ${A}, {B}$ and ${C}$ are ${m}, 2\, {m}$ and $2\, {m}$ respectively. $A$ moves towards ${B}$ with a speed of $9$ ${m} / {s}$ and makes an elastic collision with it. Thereafter $B$ makes a completely inelastic collision with $C.$ All motions occur along same straight line. The final speed of $C$ is $....\,{m} / {s}$

  • [JEE MAIN 2021]

A ball is thrown horizontally from a height with a certain initial velocity at time $t=0$. The ball bounces repeatedly from the ground with the coefficient of restitution less than $1$ as shown below. Neglecting air resistance and taking the upward direction as positive, which figure qualitatively depicts the vertical component of the ball's velocity $v_y$ as a function of time $t$ ?

  • [KVPY 2013]

Two smooth objects with a coefficient of restitution $e,$ collide directly and bounce as shown. Newton's law of restitution gives