Using the formula n = 1/sin c, the higher the n , the smaller the c . With smaller c , total internal reflection can occur over a wider range of angle of incidences . i.e. the optical fibre can bend more and total internal reflection can still occur.

There are two main types of balancing toys. Type 01: CG below the pivot point Type 02: CG above the pivot

This video goes through the basic concepts that is required for moment questions. Go through the whole video to have know the different types of questions.

Most of us know that when the treads of our typical car tyres are worn out, we need to change as to provide grip, hence our car will not skid easily. But actually, the treads of our typical car serve a more important role during rainy days. They allow the water to be displaced (quickly letting the water to move into the treads) so that the tyres can still maintain contact with the road to provide the grip. Of course, if you still go too fast on a wet road, that layer of water may not be able to be displaced in time, hence grip on the road is greatly reduced and the car is likely to skid. Especially in the recent F1 race in Singapore, due to the wet weather, the cars had to changed to hard wet tyres. Many may be puzzled why F1 cars uses smooth slick tyres during dry weather, contrary to our common sense for our typical cars. The graphic below hopes to provide some basic explanation to the wet and dry tyre and the function of the tread on tyre. Hope it helps. The following video gives a good overview of how a tyre works. There is a lot of science behind them.

Take note how to phrase the action-reaction pair, and also the differences and similarities of a action-reaction pair.

1) Newton’s first law states that an object will remain at rest or in uniform motion (constant speed) in a straight line unless an external force acts on the body. In other words, when a body is at rest or moving at constant speed in a straight line (constant velocity) , straight away you should know it is Newton’s first law . Next you must know these 3 basics concepts about 1st law: – forces acting on the body are balanced – net force / resultant force acting on the body is zero – there is no acceleration. 2) Newton’s second law states that when a net force (resultant force) acts on a body , it will cause an acceleration on the body (accelerating or decelerating). Basically F = ma where F is the net or resultant force in N,m is the mass in kga is the acceleration in ms-2 In other words, when a body is moving faster or slower (or going round a bend), you should know its Newton’s second law . Next you must know these 3 basic concepts about 2nd law: – forces acting on the body are not balanced – there is a net force / resultant force acting on the body – there is an acceleration (accelerating of net force is in the direction of motion, or decelerating if the net force is opposite to the direction of motion)