Kepler second law sates that the straight line joining the planet to the sun sweeps out equal areas in equal times this statement is equivalent to saying that

Options

A. total acceleration is zero
B. tangential acceration is zero
C. longitudinal acceraleration is zero
D. radial acceleration is zero

Answer

B

Explanation

Earth and all othere planets move around the sun under the effect of gravitational force this force always acts along the line joining the centre of the planet and the sun and is directed towards the sun
`therefore (triangle )/(trianglet)=(L)/(2m)=a` constant vector
Therefore kepler second law is the consequence of the princile of conservation of angular momentum (L)
`tau=(dL)/(dt)=0`
Now `tau = l alpha`
`therefore l alpha =0` or `alpha =0`
or `a_(T)=r alpha =0`
i.e tangential aceleration is zero