The pressure in fluids causes a force ______ (at _____ ______) to any surface.
The pressure in fluids causes a force NORMAL (at RIGHT ANGLES) to any surface.
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What equation can be used to calculate the pressure at the surface of a fluid?
pressure = force normal to a surface / are of that surface
p = F/A
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What is pressure, force and area measured in in this equation?
pressure - pascals, Pa
force - newtons, N
area - metres squared, m²
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What equation can be used to calculate the pressure of a column of liquid?
pressure = height of the column × density of the liquid × gravitational field strength
p = h ρ g
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What is pressure, height, density and gravitational field strength measured in?
pressure - pascals, Pa
height - metres, m
density - kilograms per metre cubed, kg/m³
gravitational field strength - newtons per kilogram, N/kg
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The pressure of a liquid ________ with depth (height of the column)
The pressure of a liquid INCREASES with the depth (height of the column)
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Why does the pressure of a liquid increase with depth?
There is a greater weight of liquid acting downwards
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The pressure of a liquid _________ with the density of a liquid
The pressure of a liquid INCREASES with the density of a liquid
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Why does the pressure of a liquid increase with density?
There is a greater weight of liquid acting downwards at a greater density
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What causes upthrust?
The bottom of the object is at a greater depth than the top, so the bottom experiences a greater pressure. Due to this, there is a larger force on the bottom of the object than at the top, so there is a resultant force acting upwards. This force is upthru
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What causes an object to float?
If upthrust is equal to the object's gravity
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What causes an object to sink?
If the upthrust is less than the object's weight
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The size of the upthrust acting on the object is the same as the weight of water __________ by the object
The size of the upthrust acting on the object is the same as the weight of water DISPLACED by the object
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What does it mean if an object can displace its own weight of water?
The upthrust will equal the objects weight and the object can float
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Why is it easier for an object less dense than water to float than an object the same density as water?
Objects less dense than water only have to displace a small vol of water before the weight of water displaced equals object's weight
Objects as dense as water have to displace a its own vol of water before weight of water displaced equals the object's wei
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Where would an object less dense than water float?
Where would an object at the same density as water float?
Less dense - above the surface of the water
Same density - on the surface of the water
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Why can objects more dense than water not float?
The object cannot displace a volume of water equal to its own weight. So the weight of the object is greater than upthrust so the object sinks
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What is the atmosphere?
The atmosphere is a thin layer (relative to the size of the Earth) of air round the Earth.
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The atmosphere gets ____ dense with increasing altitude.
The atmosphere gets LESS dense with increasing altitude.
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What creates atmospheric pressure?
Air molecules colliding with a surface create atmospheric pressure.
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Why does atmospheric pressure decrease with an increase in height?
The no of air molecules (+ weight of air) above a surface ↓ as the height of the surface above ground level ↑. So as height ↑ there is always less air above a surface than there is at a lower height. So atmospheric pressure decreases with an increase in h
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Why would a bag of crisps inflate inside an aeroplane?
At ground level, the air pressure inside and outside the bag is equal. When flying, the air pressure in the cabin is at a slightly lower level than air pressure on the ground. So air pressure inside bag is greater than air pressure in cabin, so bag inflat
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Other cards in this set
Card 2
Front
The pressure in fluids causes a force ______ (at _____ ______) to any surface.
Back
The pressure in fluids causes a force NORMAL (at RIGHT ANGLES) to any surface.
Card 3
Front
What equation can be used to calculate the pressure at the surface of a fluid?
Back
Card 4
Front
What is pressure, force and area measured in in this equation?
Back
Card 5
Front
What equation can be used to calculate the pressure of a column of liquid?
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