Question

A particle of mass m moves with a constant speed v along the dashed line y =

Answer 1

Angular momentum of a particle moving along a straight line is given by formula

$L = \vec r \times m\vec v$

now here particle is moving along a straight line with speed v along x direction

so here we can say

$\vec P = mv \hat i$

now we can say

$\vec L = mvr sin\theta$

here we know that

$r sin\theta = a$

so angular momentum will be

$L = mva$