fluid pressure Flashcards
(11 cards)
1
Q
fluids
A
- liquids or gases
- substances that can flow as particles are able to move around
2
Q
pressure in fluids
A
- as particles move, they collide with walls and other particles
- exert a force on the object they collide with
- pressure means a force is exerted normal (at right angles) to any surface
3
Q
what does pressure depend on?
A
- depth
- density
4
Q
how does density affect pressure?
A
- measure of compactness of a substance
- so more dense, the more particles it has so more collisions so higher pressure
5
Q
how does depth affect pressure?
A
- height of fluid above increases
- as depth increases, number of particles above that point increases
- weight of particles above adds to pressure felt
- increases force acting on object so pressure increases
- so liquid pressure increases with depth
6
Q
where is there a higher pressure?
A
deeper in water
7
Q
upthrust, how is it created
A
- resultant force upwards
- caused when a partially (or totally) submerged object experiences a greater pressure on the bottom surface than on the top surface
- as pressure increases with depth
8
Q
what is upthrust equal to?
A
the weight of fluid that has been displaced by the object
9
Q
why does an object float?
A
- if an object can displace its own weight of water so
- the upthrust is equal to the object’s weight then the forces balance and the object floats
10
Q
why does an object sink?
A
- if an object’s weight is more than the upthrust
- cannot displace enough fluid to equal its weight, denser
11
Q
upthrust effect of density
A
- if an object is less dense than fluid then it displaces a volume equal to its weight so objects weight is equal to upthrust so floats
