Particles A and B move in the same direction with angular speeds 7 rad/s and 3 rad/s. Initially B is 120° ahead of A. If A first catches B after π/N seconds, find N.

Question

G1 Physics · Accepted Answer

Initial angular separation is 120° = 2π/3 rad. Relative angular speed of A with respect to B is 7−3 = 4 rad/s. Catch-up condition: 4t = 2π/3. Therefore t = π/6 s. Hence N = 6.