Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main202621 January 2026Evening ShiftPhysicsRotational MotionActual

Two cars A and B each of mass 10³ ~kg are moving on parallel tracks separated by a distance of 10 m, in same direction with speeds 72 ~km / h and 36 ~km / h . The magnitude of angular momentum of car A with respect to car B is _ _ _ _ J.s.

Options

  1. A2 10⁵
  2. B10⁵
  3. C3.6 10⁵
  4. D3 10⁵

Correct answer

B. 10⁵

Step-by-step solution

Mass of each car m = 10^3 kg. Speed of car A , v_A = 72 km/h = 72 5 18 = 20 m/s. Speed of car B , v_B = 36 km/h = 36 5 18 = 10 m/s. Relative velocity of car A with respect to car B is v_ AB = v_A - v_B = 20 - 10 = 10 m/s. The cars are moving on parallel tracks separated by a perpendicular distance d = 10 m. The magnitude of angular momentum of car A with respect to car B is given by L = m v_ AB d . Substituting the values: L = 10^3 10 10 = 10^5 J.s. Thus, the correct option is (2).

Practice Rotational Motion on Quantrex Academy →

More from Rotational Motion

Consider a large disk of radius R and two smaller disks, each of radius r = R/50 , lying on its circumference, as shown in the figure. The smaller disks are initially in contact wi 2026A solid cylinder of radius R rolls without slipping with a center of mass speed v₀ = gR 3 on a horizontal surface with a vertical edge, as shown in the figure. Here, g is the accel 2026List-I shows four planar structures made of uniform solid rods each of mass m and length l . In the List-II the possible moment of inertia of these structures about an axis OCO' , 2026Passage: A uniform circular disk of radius 0.2 m and mass 1 kg is pivoted at its top point C such that it can rotate freely around C in the XY plane, as shown in the figure. Initia 2026Passage: A uniform circular disk of radius 0.2 m and mass 1 kg is pivoted at its top point C such that it can rotate freely around C in the XY plane, as shown in the figure. Initia 2026A solid cylinder having radius R and length L is slipping on a rough horizontal plane. At time t=0 the cylinder has a translational velocity v₀=49 m/s, perpendicular to its axis an 2026A solid sphere ( A ) of mass 5m and a spherical shell ( B ) of mass m , both having same radius, are placed on a rough surface. When a force of same magnitude is applied tangential 2026A solid sphere of radius 4 cm and mass 5 kg is rotating (rotation axis is passing through the centre of the sphere) with an angular velocity of 1200 rpm. It is brought to rest in 1 2026 Full Rotational Motion list All JEE Main PYQs