Force 2: Pressure and pressure difference in fluid & Forces and Motion & Newton’s law of motion & Momentum

Created by

Arjun Cherukuri

Cards (89)

What is pressure defined as?
The concentration of a force or the force per unit area
What can fluid either be?
Liquid or gas
What happens when an object is immersed in a liquid?
The liquid will exert pressure, squeezing the object
What does the pressure exerted on objects in fluids create?
Forces against surfaces
What angle does these forces act at?
90 degrees
Why does the pressure at a point increase with the height of the column of liquid about that point?
This is because if there is more liquid above that point, then the pressure is more
Why if there is liquid above a point is there more pressure?
The pressure in a liquid is caused by the weight of the liquid pushing against objects immersed in liquid
As the liquid becomes deeper, the amount of liquid (and weight) increase which causes the pressure to increase
In the column of water, where is the highest pressure?
Be at the bottom
What does the size of the upthrust depend on?
the density of the fluid and the volume of fluid that is displaced
What happens to the upthrust when the liquid is denser?
The greater the upthrust it will exert on an object
Why does upthrust happen?
Due to the difference in pressure between the top and bottom of the submerged object
What does if an object sink or float depend on?
The upthrust - if the upthrust on a object is equal to or greater than the objects weight, then the object will float
What happens if the upthrust is smaller than the weight?
The object will sink
What happens if the density of an object is less dense then than the fluid it is immersed in?
The object will float
What happens if the density of an object is more dense then than the fluid it is immersed in?
The object will sink
What pressure does the earth atmosphere apply at sea level?
100kPa
What happens the pressure as you go higher up in the atmosphere?
The pressure becomes less and it is less dense
Why does atmospheric pressure decrease with increasing altitude?
Air molecules collide with a surface creating atmospheric pressure
These molecules crates a force per area of the surface which creates the pressure
As you go up in altitude the number of air molecules decrease and so is the density of the air
Therefore, as height increases, there is always less air above a surface than there is at a lower height and the atmospheric pressure decreases with a increase in height
Atmospheric pressure decreases at the density of molecules decreases
What is distance?
A measure of how far an object travels
Is distance a scalar or vector quantity?
scalar
What is displacement?
Measure of how far something is from its starting position, along with its direction
Is displacement scalar or vector? 
vector
What does non-uniform motion refer to?
Motion that is changing
Typical speed of walking
1.5 m/s
Typical speed of running
3m/s
Typical speed of cycling
6 m/s
Typical speed of car
10 to 30m/s
Typical speed of passenger airplane
200-250m/s
Typical speed of sound
330-340 m/s
What quantity is velocity? 
Velocity is a vector quantity
What quantity is speed?
scalar quantity
Why is velocity always changing in a circular path?
Because the direction of travel is always changing
Example of this
International space staton
What happens to a distance time graph when the objects speed is changing?
Curves
When do you use a tangent for a distance time graph
When its a curve and your trying to find the gradient to get the speed
Acceleration definition
rate of change of velocity
In a velocity time graph how can you calculate the acceleration?
By finding the gradient
What is terminal velocity?
when air resistance balances the force of gravity, the object falls at a constant speed
What is Newton's first law?
Object will remain at rest, or move with a constant velocity unless acted on by a resultant force