A planet of mass 6 × 1025 kg is in a circular orbitof radius 4 × 1011 m around a star. The star exerts aforce on the planet of constant magnitude 1.8 × 1023 N.The speed of the planet is 3.4 × 104 m/s.
(a) In half a \"year\" the planet goes half wayaround the star. What is the distance that the planet travels alongthe semicircle?
(b) During this half \"year\", how much work isdone on the planet by the gravitational force acting on theplanet?
(c) What is the change in kinetic energy of theplanet?
(d) What is the magnitude of the change ofmomentum of the planet?
