Results

The idea of the electric field, how it's useful, and explains how the electric field is defined.

How to solve for the horizontal displacement when the projectile starts with a horizontal initial velocity. We also explain common mistakes people make when doing horizontally launched projectile problems.

Forces at a distance are explained by fields (gravitational, electric, and magnetic) permeating space that can transfer energy through space. Magnets or electric currents cause magnetic fields; electric charges or changing magnetic fields cause electric fields.

Magnetism is an interaction that allows certain kinds of objects, which are called ‘magnetic’ objects, to exert forces on each other without physically touching. A magnetic object is surrounded by a magnetic ‘field’ that gets weaker as one moves further away from the object. A second object can feel a magnetic force from the first object because it feels the magnetic field of the first object. The further away the objects are the weaker the magnetic force will be.

• Predict, qualitatively, how an external force will affect the speed and direction of an object's motion.
• Explain the effects with the help of a free body diagram.
• Use free body diagrams to draw position, velocity, acceleration and force graphs and vice versa.
• Explain how the graphs relate to one another.
• Given a scenario or a graph, sketch all four graphs.

This online interactive lesson discusses what reflections are and provides examples of reflections.