Results

There are some key words that you need to know for circles: radius, circumference, diameter, sector, segment, tangent, chord and arc. In this video you will discover what they all mean.

This video discusses the topic of circles.

This video explains the equation of a circle.

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.

• 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 YouTube video explains how river basins are formed.

This YouTube documentary highlights the ecological and socio-economic importance of the Tana River Basin in Kenya.

This 32 minute long YouTube video investigates the water contamination problems in Tanzania, with specific focus on Dar Es Salaam. 

This 11 minute long YouTube video describes the various causes and types of water pollutants.

This YouTube video investigates what water pollution is and some examples and effects of water pollution.