JEE Class main Answered

Let us consider the particle of mass m is moving along the line y = x +5 .

Let its speed be v .

When the particle is at P(x,y) , its angular momentum is given as

  ........................(1)

where is position vector of point P, is linear momentum , θ is angle between position vector

and momentum vector and is unit vector along z-axis .

θ = 45^o - α  [ because slope of line y = x+5 is  1 or tan45 . Hence APB = 45^o ]

By substituting  sinθ in eqn.(1) , we get