P11 - Force & Pressure 2️⃣✅ Flashcards
What is pressure?
The force per unit area
What is the unit of pressure?
Pa, Pascals
What is the equation for pressure?
Pressure (Pa) = force (N) / Area (m2)
P = f/a
What is the equation for weight/force(N)?
Force (N) = mass (kg) x gravity (9.8)
F = m x g
What is the symbol for pressure?
The letter ‘p’
What is the symbol for liquid density?
The Greek letter rho ‘ρ’
What is the equation for density?
Density = mass (kg) / volume (cm3)
ρ = m/v
What is the equation for liquid pressure?
Pressure (Pa) = (liquid) density (kg/m3) x gravity (N) x height (m)
P = ρ x g x h
The smaller the pressure the __________ the area
bigger
The greater the pressure the ___________ the area
smaller
1 kilonewton = ?N
1000N
How do you get from kilonewtons to newtons?
X by 1000
How do you get from newtons to kilonewtons?
divide by 1000
1 kilopascal= ?Pa
1000Pa
How do you get from kilopascals to pascals?
X by 1000
How do you get from pascals to kilopascals?
divide by 1000
What is atmospheric pressure?
air molecules colliding with surfaces - every time they hit a surface they exert a small force, but because it happens so frequently & there are so many collisions it eventually equals air pressure (like a net force)
What is upthrust?
An upwards force on a body in a fluid
What is Archimedes principle?
The size of upthrust is equal to the weight of the fluid that has been displaced
e.g. upthrust = weight of fluid displaced
If an object has a density less than the fluid its in it ______?
floats
If an object has a density the same as the fluid it __________
suspends e.g floats in the liquid but is submerged
If an objects has a density greater than the fluid its in it ______?
sinks
What is a fluid?
A substance that can flow (liquid or a gas)
What is the unit for area in the pressure equation?
m2
What is the unit for density?
g/cm3 or kg/m3
Atmospheric pressure ____________ with an increase in height.
Atmospheric pressure decreases with an increase in height.
As depth increases pressure ________________
As depth increases pressure also increases
Why is pressure greater when deeper?
Because as you go further down their is a greater weight of waster pushing down therefore a higher pressure
