Upthrust And Atmospheric Pressure

Question 1

what happens when an object is submerged into a fluid

Answer 1

the pressure of the fluid exerts a force on it from every direction

Question 2

how would the force exerted on an object in a fluid change if the depth changes

Answer 2

• the pressure increases with depth

- so the force exerted on the bottom of the object is larger than the force exerted at the top of the object

Question 3

what is the effect of a larger force being exerted on the bottom of an object than the top

Answer 3

• it causes the creation of a resultant force upwards
• otherwise known as a force pushing the object out of the fluid
• known as upthrust

Question 4

what is upthrust equal to

Answer 4

• the weight of the fluid that had been displaced by the object
• the upthrust on a boot in water is equal to the weight of a boot-shaped volume of water

Question 5

when does an object float

Answer 5

• when the upthrust on an object is equal to the objects weight
• causing the forces to balance

Question 6

when does an object sink

Answer 6

when the weight of the object in the fluid is more than the upthrust acting upon it

Question 7

if the relationship between weight and upthrust determines whether an object floats or sinks in a fluid, what is the umbrellaring factor that determines whether an object will float or not and why

Answer 7

• the density of the object
• the amount of fluid the object will displace is determined by its surface area or volume
• the formula for density is density = mass / volume
• if the object is denser than the fluid its placed in, it means that it doesnt have enough volume to displace the correct amount of water (in terms of weight) in order for the upthrust to be equal
• but the mass is high compared to its volume
• and as weight = mass x gravity
• higher weight means it cant displace enough fluid to equal its high weight or mass

Question 8

what will an object that is less dense than the fluid it placed in do to the fluid

Answer 8

• it will displace a volume of the fluid that is equal to the its weight
• before it is completely submerged

Question 9

what is the weight and upthrust of an object that has been completely submerged into a fluid ans what does that cause

Answer 9

• the weight of the object is equal to the upthrust

- causing the object to float

Question 10

what will an object that is denser than the fluid it is placed in do to the fluid

Answer 10

• it is unable to displace enough fluid equal to its weight
• meaning that its weight is always larger than the upthrust
• causing it to sink

Question 11

how do submarines make use of upthrust

Answer 11

• to sink, large tanks are filled with water to increase the weight of the submarine
• so that it is more than the upthrust
• to rise to the surface, the tanks are filled with compressed air
• to reduce the weight so that it is less than the upthrust

Question 12

what is the atmosphere

Answer 12

• a layer of air that surrounds the earth

- it is thin compared to the size earth

Question 13

how is atmospheric pressure created on the surface

Answer 13

by air molecules colliding with the surface

Question 14

what is the relationship between altitude and atmospheric pressure

Answer 14

• as the altitude increases
• the atmospheric pressure decreases
• the atmospheric pressure would accelerate in its decrease for each unit of elevation
• because atmospheric pressure is affected by the density of the atmosphere, which also varies with height

Question 15

why does the atmospheric pressure decrease as the altitude increases

Answer 15

• because the atmosphere itself gets less dense
• as more particles rest at surface level
• which means there are less particles to collide with the surface abd surroundings

Question 16

what is the effect of fewer air molecules being above a surface as the height increases

Answer 16

• it means the weight of the air above it
• which contributes to atmospheric pressure
• decreases with altitude