What makes some collisions elastic and others inelastic?

If the collision involves bouncing, it is elastic.

If the collision involves sticking together, it is elastic.

If there is no loss of kinetic energy in the collision, it is inelastic.

If there is energy lost in the collision to sound, heat, etc., the collision is inelastic.

If a stone with an original velocity of 0 is falling from a ledgeand takes 8 seconds to hoybthe ground whays the final velocity of the stone

What are the similarities & differences between a thermistor and a light dependent resistor in physics?

In this thread, i would like you to comment on the nature of light and how operation of telescopes. light has a duality of a particle and a wave; which one affects your life? also how does light interact with optics inside telescopic systems? answer these questions in two paragraphs. then respond the another students response.