Question

question 1 - 10
what role does gravity play in determining a planets motion?
gravity does not have an effect on planet motion.
gravity causes planets to move at the same speed.
gravity causes planets to follow different orbital paths.
gravity positions planets at equal distances from the sun.

Explanation:

Gravity is a fundamental force in the universe. According to Newton's law of universal gravitation, every object with mass attracts every other object with mass. In the context of planetary motion, the Sun's gravity exerts a force on the planets. This gravitational force acts as a centripetal force. A centripetal force is a force that makes a body follow a curved path. For planets, this results in them following orbital paths around the Sun. Different planets have different masses, velocities, and distances from the Sun. The combination of these factors, along with the gravitational force from the Sun (and to a lesser extent, gravitational forces from other planets), causes each planet to have its own unique orbital path.

Let's analyze each option:

• Option 1: Gravity is a crucial force in the universe, especially in celestial mechanics. It has a significant effect on planet motion. So, this option is incorrect.
• Option 2: Planets have different orbital speeds. For example, Mercury, being closer to the Sun, has a much higher orbital speed (average orbital speed of about 47.87 km/s) compared to Neptune (average orbital speed of about 5.43 km/s). Gravity does not cause them to move at the same speed. This option is incorrect.
• Option 3: As explained above, the gravitational interaction (mainly with the Sun) causes planets to follow their own orbital paths. This option is correct.
• Option 4: Planets are at different distances from the Sun. Mercury has an average distance of about 57.9 million km from the Sun, while Neptune has an average distance of about 4.5 billion km from the Sun. Gravity does not position them at equal distances. This option is incorrect.

Answer:

Gravity causes planets to follow different orbital paths.