Will the angular momentum of a planet be conserved? Justify your answer.

Explanation

The torque experienced by the Earth due to the gravitational force of the Sun is given by,
`vec(tau)=vec(r)xxvec(F)`
`=vec(r)(-(GM_(S)M_(E))/(r^2)hatr)=0`
Since `vec(r)=rhat(r),(hat(r)xxhat(r))=0`
So, `vec(tau)=(dvec(L))/(dt)=0`
It implies that angular momentum `vec(L)` is a constant vector. Hence L is conserved.