Physics

Conduction, convection, radiation

Conduciton: Touching material, solid, liquids, gases. Movement form hot to cold. Metals= good conductors (poor insulators) Nonmetals= good insulators (poor conducotrs), Vacuum= best insulaltor

Convection. Movement of fluids, liquids, gases. Hot air wil rise, cold air will sink (convection current). To reduce convection, keep air trapped ore remove it entirely (vacuum).

Radiation (infrared/ thermal): Electromagnetic wave, Can travel through a vaccum (does not need a medium). Dark/ matte surfaces: good absorbers and emitters. Light/ shiny surfaces: good reflectors.

Movement

What it is

examples

Space

Orbits of planets are elliptical. Planets have nearly circular orbits (planets orbits stars)

Moons have nearly circular orbits (moons orbit planets)

Comets have very elliptical orbits (tail will always face away form the sun) 

Practise Question on orbital speed

Jupiter: T = 12 years = (12x365x24) =105120

r= 764 000 000km

v= ?km/hr.         Need to be the same

v= 2π(764 000 000)÷ 105120 = 45665 km/hr [5 s.f]

Rules for distance time graphs

1) The gradient (slope) at any point gives the speed of the object

2) Flat sections are where its stopped

3) A steeper curve means it's going faster

4) Curves represent acceleration

5) A curve getting steeper means it's speeding up (increasing gradient) 

6) A levelling curve means it's slowing down (decreasign gradient)

rules of a velocity time graph:

1) Gradient= acceleration

2) Flat sections represent steady speed

3) The steeper the graph, the greater the acceleation or deceleration 

4) Uphill section ( / ) are acceleration

5) Downhill sections ( \ ) are deceleration

6) The area under any part of the graph is equal to the distance travelled in that time interval

7) A curve means changing acceleration\