Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Gravitation

Question:

In planetary motion the areal velocity of position vector of a planet depends on angular velocity (r) and the distance of the planet from sun (r). If so the correct relation for areal velocity is :

Options:

dA/dt ∝ ω r

dA/dt ∝ ω2 r

dA/dt ∝ ω r2

dA/dt ∝ √ωr

Correct Answer:

dA/dt ∝ ω r2

Explanation:

\(\frac{dA}{dt} = \frac{L}{2m}\)

   =\(\frac{mvr}{2m}\)

   =\(\frac{1}{2}\omega r^2\)

[As Angular momentum L = mvr and v = rω] 

\(\Rightarrow \frac{dA}{dt} \propto \omega r^2\)