Unit 3 - Motion, gravity and our solar system

Content

• Force of gravity and its relation to the mass of big objects in the Solar System (Earth vs. Moon)
• Acceleration and Force: how motion of objects are affected by mass and amount of force.
• Mass and weight and concepts behind a gravitational field (force per unit mass, as in "g" of Earth = 10 Newtons/kilogram)
• Relationship of inertia and mass.
• Gravitational force between big objects, circular motion in the Solar System, orbits (elliptical, vs. circular), path
• Newton's law of universal gravitation , force is proportional to mass of objects and inversely proportional to distance squared.
• Space exploration impact on modern technology , benefits and costs.

Skills and understanding

• Relate time and distance, resulting in speed
• Apply the concept of 'gravity' as a force that changes the speed difference between mass and weight (apply F=mg), on different planets?
• Visualise objects in an orbit around the earth as continuously falling
• Understand the challenges of space exploration programs are related to lack of gravity and air.
• Use Newton's second law:- an unbalanced force will cause an object to speed up, slow down or change direction
• Use Newton's first law:- balanced forces (or no forces) will mean an object either stays at rest or continues at constant velocity.