Fields and forces. Gravitational force and field. 6.1.1 State Newtons universal law of gravitation. 6.1.2 Define gravitational field strength. 6.1.3 determine the gravitational field due to one or more point masses. 6.1.4 Derive an expression for gravitational field strength at the surface of a planet, assuming that all its mass is concentrated at its centre. 6.1.5 Solve problems involving gravitational forces and fields. Electric force and field. 6.2.1 State that there are two types of electric charge. 6.2.2 State and apply the law of conservation of charge. 6.2.3 Describe and explain the difference in the electrical properties of conductors and insulators. 6.2.4 State Coulombs law. 6.2.5 Define electric field strength. 6.2.6 Determine the electric field strength[] due to one or more point charges. 6.2.7 Draw the electric field patterns for different charge configurations. 6.2.8 Solve problems involving electric charges, forces and fields. Magnetic force and field. 6.3.1 State that moving charges give rise to magnetic fields[]. 6.3.2 Draw magnetic field patterns due to currents. 6.3.3 Determine the direction of the force on a current-carrying conductor in a magnetic field. 6.3.4 Determine the directrion of the force on a charge moving in a magnetic field. 6.3.5 Define the magnitude and direction of a magnetic field. 6.3.6 Solve problems involving magnetic forces, fields and currents.