1. Gravity: The sun's immense mass exerts a gravitational pull on the planets, constantly trying to pull them inwards.
2. Inertia: Planets are moving forward in a straight line due to their inertia, the tendency of an object to resist changes in motion.
How they work together:
* Gravity acts as the centripetal force, constantly pulling the planet towards the sun.
* Inertia keeps the planet moving forward in a straight line.
* The combination of these two forces results in the planet following a curved path, which is the planet's orbit.
Imagine a ball on a string being swung around in a circle. The string represents the force of gravity, pulling the ball inwards. The ball's momentum keeps it moving forward, and the tension in the string prevents it from flying off in a straight line. This is analogous to how planets stay in orbit around the sun.
