P6 - matter, models, and explanation Flashcards
What is the formula for pressure in a solid
Pressure = Force/Area
What is the measure of pressure
Pascals
Ifan object is submerged in a liquid, what causes forces to be exerted on it
Pressure from surrounding particles
The pressure from the water weight above it
What is the formula for pressure on an object in a liquid
P = hpg
(h = height above object)
(p = density)
(g = gravity)
What causes upthrust on an object
The fact that the bottom is deeper than the top, so more force is exerted upwards
What causes objects to sink
If they are more dense than the liquid, or if their weight generates more force than the upthrust gives them
Why is there more pressure at sea level
Because there are more collisions with air particles, so more force, so more pressure
What is the birth of a star
Cloud of gas and dust called nebula, is brought together by gravity, making a protostar. As the gravity increases, the pressure increases, and so does the temperature, which causes nuclear fusion to start, making a star.
What is the death of a star
When the fusion runs out of hydrogen fuel, the force of gravity starts to compress the star. This makes it dense enough and hot enough for fusion to re start, and this makes all elements up to iron in the periodic table, and makes the star expand
What does a small to medium star create after it has collapsed
A red giant
What does a very large star create after it has collapsed
A red supergiant
What is the life cycle of a red giant
It becomes unstable, and expels its outer layers of gas, revealing a hot, dense, solid core. This core does not undergo nuclear fusion, and is called a white dwarf. After the dwarf cools, it stops emitting light, and becomes a black dwarf.
What is the life cycle of a red supergiant
It shines brightly, as more nuclear fusion occurs. After several expansions and contractions, it exploded. This expelled elements heavier than iron across the universe, and is called a supernova. Very big stars will then make a dense core, called a neutron star. Massive stars might collapse in on themselves, forming a black hole.
What is elastic deformation
Where the object will return to its original shape
What is inelastic deformation (or plastic deformation)
When the object will not return to its original shape
