physics unit 2

Afar Africa: why did the crack form?

vector

a mathematical quantity that has a direction and magnitude. represented by an arrow.

magnitude

the size or amount of a quantity; for vectors, it’s the length or numerical value.

force

the push or pull on an object that causes a change in its motion.

plate boundaries

edges where Earth’s tectonic plates meet and interact (divergent, convergent, transform).

tectonic plates

large sections of Earth's lithosphere that move and interact with one another, causing geological activity such as earthquakes and volcanic eruptions.

sediment

particles of rock, minerals, or organic material transported and deposited by wind, water, or ice.

newton

the standard unit of force in the International System of Units (SI). 

the force required to accelerate a one-kg mass at a rate of one meter per second per second (1N=1kg⋅m/s²)

stable

when forces are balanced; the object/system shows no net change in motion or position.

• scale challanges this

free body diagram (fbd)

a sketch showing an object and all external forces acting on it as labeled vectors.

fg

force of gravity (weight), acting toward Earth’s center; (Fg = mg)

ff

force of friction, opposing relative motion between surfaces.

fpull

applied pulling force from a rope, hand, or another object.

fpush

applied pushing force from contact.

fair

air resistance (drag), a friction-like force opposite an object’s motion through air.

fn

normal force; support force perpendicular to the surface of contact.

velocity

the rate of change of position with respect to time. Common units: m/s, km/h; vector quantity.

net force

vector sum of all forces on an object; determines acceleration

compression testing machine

used to determine the compressive strength and other mechanical properties of rock samples by applying a controlled force until failure.

m - e - f

matter ⟶ energy ⟶ force

matter - nothing changes at rest (it is stable because the surrounding forces are balanced)

energy - can be stored or released, when it is transfered into matter, it caused the matter to change by unbalancing forces)

force - balanced (0 Fnet) or unbalanced (greater than 0 Fnet)

p wave

primary waves are produced after earthquackes that can travel through solids and liquids, they are a type of sound wave.

• cannot pass through shadow zone

s wave

secondary waves are produced after earthquackes which can only travel through solids.

• large shadow zone

earth’s layers

crust - outermost layer, the lithosphere (P, S)

mantel - thickest (P, S)

outer core - liquid layer (P)

inner core - liquid layer (P)

rigitity in relation to the mantle

how stiff or resistant a material is to being deformed or bent.

in the earth’s mantle, rigidity determines how rocks inside will respond to push + pull forces.

more rigid mantle: resists deformation + transfers seismic waves faster.

less rigid mantle: bends or flows more easily and slows the tranfer of seismic waves.

heterogeneuos 

something made up of diverse and un-uniform parts

density

density is how dense the particles of matter are.

low density: allows for slow waves,

high density: allows for fast wavs,

mantle model

red: surface volcanic presance, likely earthquake prone

blue: mountains and hills, high density structures, earthquake prone

dark colours: major surface structures, plate boundaries (as a result of unbalanced forces)

light colours: few surface structures, solidly on a plate (balanced forces)

seismic waves

vibraions that travel through the earth caused by events like earthquakes and valcanoes. the two kinds are s and p waves.

elastic limit

the maximum stress a meterial can withstand by a force before it is permanantly deformed

permanant deformation

the irreversable change in the shape or size of an object that remains after the applied force is removed. occurs after stressed beyond elastic limit.

atom formation under afar

long ago (stable, forces balanced) more recent (three forces acting upon region, forces un balanced) at the time of the crack (elastic limit reached, ground pulled apart by forces, energy released)

gps plate direction map

shows the cm/year (magnitude, velocity, direction) that plates travel with vectors.

why is the mantle exerting

high vs. low density

high: cooler, once atoms’ energy is transfered from into the crusts’ atomic bonds the slow atoms begin flow closer together, and are pushed down by the Fg.

low: hotter, excited atoms thin out as they are moved up by the Fbuoyant Force (which is stronger than the Fg)

convection

the transfer of heat through the movement of a liquid .

convection test question

draw model , elastic limit , mef how it plays a role