Figure 7.4 shows two identical particles 1 and 2, each of mass m, moving in opposite directions with same speed v along parallel lines. At a particular instant, r₁ and r₂ are their respective position vectors drawn from point A which is in the plane of the parallel lines. Choose the correct options:

As we know that

And direction of L is perpendicular to both the vector

According to question,

Angular momentum for particle1 about A is

(upward from right hand thumb rule)

Similarly,

(taking upward as positive)

Total angular momentum

(taking upward as positive)

(taking downward as positive)

Hence option an and d are correct.