Physics

Problem

At a point P outside an isolated planet, the radial derivative of gravitational potential is measured to be

\dfrac{dV}{dr}=+3.0\times10^{6}\,\text{J\,kg}^{-1}\,\text{m}^{-1}

, where

r

is the distance measured outward from the planet’s centre. Which statement about the direction of the gravitational field

\vec g

at P is correct? a)

\vec g

is directed radially outward, away from the planet b)

\vec g

is tangential to a circular path at P c)

\vec g

is directed radially inward, towards the planet d)

\vec g

is zero at P