Paper 2 physics Flashcards
why is atmospheric pressure lower higher up
density of particle decreases - fewer collisions - lower pressure
fewer air molecules above a surface and decreases atmospheric pressure
what is upthrust and how is it found
force exerted on bottom of object greater than force exerted on the top creates an upthrust - equal to the weight of fluid that has been displaced
why does something float
if upthrust equals the objects weight it floats - as the water pushing it up due to its displacement is equal in force (weight) to the weight of the object
why does something sink
it cannot displace enough water to produce a large enough upthrust to balance its own weight down as its volume isn’t large enough - to do with density
inertia
tendency to continue in uniform motion
typical thinking and braking distance for a 30mph car
9m thinking, 14m braking and 6 car lengths total
typical thinking and braking distance for a 50mph car
15m thinking, 38m braking and 13 car lengths
typical thinking and stopping distances for 70mph car
21m + 75m (braking)
24 car lengths total
what is typical reaction time
0.2 to 0.9 secs
during refraction what remains the same even though speed changes
frequency obvs as no change in energy
higher refractive index = more/less refraction
more
why is rough surface diffuse reflection
normal different for each point
what angle is the reflection of parallel rays in specular reflection
same - as opposed to diffuse reflection
as temp increases the what decreases
peak wavelength - obvs as energy higher intensity higher
chapter 14 - lenses maybe look over. the situations?
