Physics Revsion Flashcards
Units
Femto
Pico
Nano
Micro
Milk
Metre
Kilometre
Mega meter
Giga
Tera
PETA
Why greater mass same volume fall faster
Greater mass means greater weight, to achieve free fall the resistive forces must equal the weight so resultant force is 0 and it travels at constsnt accelrwtion
A greater weight means greater resistance
As velocity proeprinsl to resistance squared, this means greater velocity
However if different surface areas this won’t work
Assuming constsnt mass newton second Ka was without
F= ma , otherwise rate of change if momentum
And as mass changes under high speeds, then this is broken and rate of change of momentum e must be used
Centre of mass where all the mass can be thought to be concentrated assuming uniform density
An object will come. To rest with its centre of mass below the point of suspension as the minimum gpe area
This is because the weight acts through the pivot such that no rotational moment is felt
Principle of moments , for a body I nrotetiinal EQUILIBIRUM sun if anti = c,ockwise
Equilibrium the miners about any plane 0 and resultant force about any plane 0
Pressure in liquids
Remember that total pressure is atmospheric and sea too
Pressure Is due to weight of coloumn kf water above it oishign down (even if above it is no longer water I guess)
At the bottom of something, there will be higher pressure than top, resulting in a resultant pressure, and pressure x area gives a force upwards = upthust
Upthust is thus = to change in pressure x area
Which is change in height x g x density if water x area
The upthust experienced is always equal to the weight of fluid displaced
And this can be calculated by volume of fluid displaced = volume of the thing In water x density if water x g
And you know if ‘tis floating then it means 0 resultant force so outburst = to weight
Can find out fractions too, because you can rearrange
At the end of the day it shows that what determines if it sinks or not = density
Density if object / density if fluids
Ice density of ice compared to water
Ice is less than water because for same mass ice takes larger volume because bonds held in an open altitude
Okay so ice less density, ti will thus sink to 9/10 down
Ice melt volume decrease
