summary of the lectures on 26th

FOR IGCSE

8th -  Problem solving on graphical method of representing motion.
key points - area under the curve of Speed time graph gives you distance.
for finding the gradient of speed time graph should have a big triangle on the curve to find the acceleration from the graph.

9th - Dispersion from the prism
White light enters in the prism and split into 7 colors
where RED deviate least and the VIOLET deviate most
Thats why the red light is used to represent the danger sign.

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IB

The elastic collision
An elastic collision is an encounter between two bodies in which the total kinetic energy of the two bodies after the encounter is equal to their total kinetic energy before the encounter. Elastic collisions occur only if there is no net conversion of kinetic energy into other forms.

An inelastic collision is a collision in which kinetic energy is not conserved (see elastic collision).

In collisions of macroscopic bodies, some kinetic energy is turned into vibrational energy of the atoms, causing a heating effect, and the bodies are deformed.

The molecules of a gas or liquid rarely experience perfectly elastic collisionsbecause kinetic energy is exchanged between the molecules' translational motion and their internal degrees of freedom with each collision. At any one instant, half the collisions are – to a varying extent – inelastic (the pair possesses less kinetic energy after the collision than before), and half could be described as “super-elastic” (possessing more kinetic energy after the collision than before). Averaged across an entire sample, molecular collisions are elastic.