Question

What happens to Centripedal force on the planet around a star if the radius of an orbit is doubled ? assume that velocity remains the same A) the Centripedal force will be half of its original value B) the Centripedal force will be double its original value C) the Centripedal force will be 1/4 of its original value D) the Centripedal force will not change

Answer 1

We will have the following:

We know that:

$F_c=\frac{mv^2}{r}$

If we double the radius, then:

$F_c=\frac{mv^2}{(2r)}\Rightarrow F_c=\frac{1}{2}\frac{mv^2}{r}$

So, the centripetal force will be half of its original value. [Option A]