Question 1: Define the term 'planet' according to the International Astronomical Union.

Answer: A celestial body that orbits the Sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and has cleared its orbital neighbourhood.

Question 2: List the four terrestrial planets in order from the Sun.

Answer: Mercury, Venus, Earth, Mars

Question 3: Explain why planets orbit the Sun in roughly circular paths rather than in straight lines.

Answer: Planets orbit the Sun in roughly circular paths due to the gravitational force exerted by the Sun, which provides the centripetal force needed for orbital motion, resulting in a stable, curved trajectory.

Question 1: Calculate the orbital speed of Earth around the Sun given that the average distance from the Sun to Earth is 1.496 × 10^11 m and the orbital period is 365.25 days. Use the formula: Speed = Distance / Time. Express your answer in km/s.

Answer: 29.78 km/s

Question 2: The mass of the Sun is approximately 1.989 × 10^30 kg. Calculate the gravitational force between the Sun and Earth using Newton's law of gravitation: F = G * (m1 * m2) / r^2, where G = 6.67 × 10^-11 N m^2/kg^2, m1 = mass of Sun, m2 = mass of Earth (5.972 × 10^24 kg), r = 1.496 × 10^11 m.

Answer: 3.54 × 10^22 N

Question 1: Describe a simple experiment to demonstrate the effect of gravitational attraction between two objects in a classroom setting. Include variables that could be controlled and safety precautions.

Answer: A possible experiment involves using a lightweight, small mass (like a marble) placed on a smooth surface and a larger mass (like a heavy ball) to show the attraction. By observing the deflection or movement of the small mass when the larger mass is nearby, students learn about gravitational effects. Controlled variables include the mass of the objects and the distance between them. Safety precautions include ensuring the surface is stable and that heavy objects are handled carefully to prevent injury.

Question 1: A planet has an orbital period of 2 Earth years and an average distance from its star of 3 × 10^11 m. How does its orbital velocity compare to Earth's? Explain your reasoning.

Answer: Since the orbital period is longer and the distance is greater, the planet's orbital velocity is lower than Earth's. Using the relation velocity = 2πr / T, a longer period (T) and larger radius (r) result in a slower orbital speed.

Question 1: Discuss how understanding planetary orbits and gravitational forces is crucial in the development and operation of satellite technology used for GPS and communications.

Answer: Understanding planetary orbits and gravitational forces allows engineers to accurately position and maintain satellites in stable orbits, ensuring reliable GPS signals and communication links. Knowledge of gravitational influences helps in planning satellite trajectories, avoiding collisions, and predicting orbital decay or perturbations caused by other celestial bodies.