1. Tardigrade
  2. Question
  3. Physics
  4. Two small particles of equal masses start moving in opposite directions from a point A in a horizontal circular orbit. Their tangential velocities are v and 2 v respectively, as shown in the figure. Between collisions, the particles move with constant speeds. After making how many elastic collisions, other than that at A, these two particles will again reach the point A ?

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. Two small particles of equal masses start moving in opposite directions from a point $A$ in a horizontal circular orbit. Their tangential velocities are $v$ and $2 v$ respectively, as shown in the figure. Between collisions, the particles move with constant speeds. After making how many elastic collisions, other than that at $A$, these two particles will again reach the point $A$ ?Physics Question Image

IIT JEEIIT JEE 2009System of Particles and Rotational Motion

Solution:

At first collision one particle having speed $2 v$ will rotate $240^{\circ}$ $\left(\right.$ or $\left.\frac{4 \pi}{3}\right)$ while other particle having speed $v$ will rotate $120^{\circ}$ (or $\left.\frac{2 \pi}{3}\right)$.
At first collision they will exchange their velocities. Now as shown in figure, after two collisions they will again reach at point $A$.

Solution Image