Question

how does gravitational force exerts on sun and other planets?

Answer 1

Like all objects with mass, planets have a tendency to resist changes to their direction and speed of movement. This tendency to resist change is called inertia, and its interaction with the gravitational attraction of the sun is what keeps the planets of the solar system, including Earth, in stable orbits. The planets have occupied these nearly-circular orbits since the formation of the solar system, and they won't be leaving them anytime soon.Moons are sufficiently close to their planet for the gravitational force between them and the planet to dominate the force between them and the distant Sun. Hence moons orbit their planet and the planet-moon system orbits the Sun.Asteroids mostly orbit in the asteroid belt between Mars and Jupiter but they can get knocked out of there into an orbit that brings them into collision courses or near-misses with planets including Earth. They are hard to see until they get close to Earth so there is some danger that we may get hit by one without warning!
As it moves in its orbit, a planet has a forward momentum, which is defined as the product of its velocity and its mass. In the absence of other forces, a planet's momentum would carry it straight out into space. The gravitation of the sun, however, is a formidable force, and it's also one that is proportional to the planet's mass. However, the sun's gravitational field doesn't oppose or amplify the planet's forward motion; if it did, the planet would gradually spiral toward the sun or away from it. Instead, the force of gravitation acts in a direction that is almost exactly perpendicular to the planet's forward motion.
hope it helped.