JEE Main 2026 — Jan 21, Shift 2 — Physics solution

JEE Main2026Jan 21, Shift 2Physics

Two cars A and B each of mass $1 0^{3}$ 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.

A
$3.6 \times 1 0^{5}$
B
$1 0^{5}$
C
$3 \times 1 0^{5}$
D
$2 \times 1 0^{5}$

Solution

Angular momentum of A with respect to B uses the relative velocity of A as seen from B, and the perpendicular separation between the tracks.

Relative speed: $v_{r e l} = 72 - 36 = 36$ km/h $= 36 \times \frac{5}{18} = 10$ m/s.

Perpendicular distance: $r_{⊥} = 10$ m.

$∣ L ∣ = m v_{r e l} r_{⊥} = 1 0^{3} \times 10 \times 10 = 1 0^{5}$ kg m $^{2}$ /s.

← Back to full paper

Practice more Physics

Concept-wise practice with instant solutions on Fundamenthol.

Start practicing →