Forces and Pressure Ch3 Flashcards
what is the equation for moment
force x distance
around a pivot or folcrum
what are the principles of moment
- if at equilibrium, the moments on both sides of the pivot must be the same
- if multiple forces are acting, their sum (moment) must be equal if at equilibrium [zero]
how is the centre of gravity influenced
- lowering the centre of mass increases stability
- wider base increases stability
what are the three types of stability
A) stable: requires significant force to shift the centre of mass
B) unstable: requires little force to shift the centre of mass
C) neutral: regardless of the force applied, centre of mass remains at the same point
what does elastic mean
an object that if stretched or compressed it will return to its original shape
what does elastic limit mean
when a object is stretched or compressed beyond it’s point of return
what is Hooke’s law
Hooke identified that there is a proportionality between the extension of a spring and the load
the extension of the spring/ the load of weight = is always the same
what is the equation for spring constant
load/ extension
what is pressure
pressure is the force applied on an area
what is the equation for pressure
force/ area
what are the properties of a liquid pressure
A) pressure acts an all directions
B) pressure increases with depth
C) pressure depends on the density of the liquid ie denser=greater pressure
D) pressure doesn’t depend on the shape of the container
what is the equation for pressure in liquids
density x gravity x depth
p=pgh
what are the properties of air pressure
A) pressure acts on all directions
B) pressure decreases as you rise
what tool do we use to measure atmospheric pressure
barometer
altimeter
manometer
how does a barometer work
mercury is used beacuse:
- its a liquid, so its non compressible but fills a container
- its a metal, so it has a height density which allows reasonable height changes
