Question 1: Define gravity and explain how it affects objects near the Earth's surface.

Answer: Gravity is a force of attraction exerted by the Earth on objects, pulling them towards its centre. It causes objects to fall when dropped and gives them weight.

Question 2: Describe the mechanism by which gravity keeps planets in orbit around the Sun.

Answer: Gravity is a force of attraction between the Sun and the planets. The planets move at a speed that balances this gravitational pull, resulting in an orbit.

Question 1: Calculate the weight of an object with a mass of 5 kg on Earth. Use the acceleration due to gravity g = 9.8 m/s². (Weight = mass × gravity)

Answer: 49 N

Question 2: An astronaut with a mass of 70 kg is on the Moon, where the acceleration due to gravity is approximately 1.6 m/s². What is the astronaut's weight on the Moon?

Answer: 112 N

Question 1: Describe a simple experiment to demonstrate that all objects fall at the same rate regardless of their mass, assuming air resistance is negligible.

Answer: Drop objects of different masses (e.g., a feather and a metal ball) from the same height in a vacuum or in a controlled environment where air resistance is minimal, and observe that they hit the ground simultaneously.

Question 2: List two safety precautions to consider when conducting experiments involving falling objects.

Answer: Ensure the area below the experiment is clear of people to prevent injury, and use protective gear such as safety goggles.

Question 1: A satellite orbits the Earth at an altitude where the gravitational acceleration is 8.7 m/s². If the satellite's mass is 500 kg, what is the gravitational force acting on it?

Answer: 4350 N

Question 2: Explain how the variation in gravitational acceleration at different altitudes affects satellite orbits.

Answer: At higher altitudes, gravitational acceleration decreases, which affects the satellite’s orbital speed and stability. Satellites at higher orbits experience weaker gravity, requiring adjustments in velocity to maintain their orbit due to the inverse-square law of gravity.

Question 1: Describe how understanding gravity is important in designing safe roller coaster rides.

Answer: Engineers must calculate gravitational forces and accelerations to ensure the ride is safe, controlling g-forces experienced by riders and preventing excessive stress on the structure.

Question 2: Identify two industries that rely heavily on principles of gravity and explain their importance.

Answer: Aerospace industry for satellite deployment and space exploration, and civil engineering for constructing stable foundations in buildings and bridges.