P11 Force and Pressure Flashcards
Pressure
Is the force normal to a surface divided by the surface
P= F/ A
Unit for pressure
Pascal (Pa), which is equal to 1 N/ m squared
What happens to pressure in liquid when incraese depth
The pressure incraeses (greater force)
When does a liquid stop flowing
When the pressure along the same horizontal level is constant
How does the density of a liquid effect the pressure
The greater the density the greater the pressure in the liquid
Equation for the pressure of a liquid column
P = h x p x g Pressure = height x density x gravitational field strength
How do air molecules create pressure
By colliding with surfaces
How does higher altitudes effect atmospheric pressure
It decreases because there is less air
What happens to the density of the atmosphere as you increase in altitude?
It decreases
What’s the force on a flat object due to a pressure difference equal to?
The pressure difference x the area of the flat surface
What’s upthrust on an object in a fluid?
Is an upward force on the object due to the fluid
What causes upthrust on an object?
The pressure of the fluid
What does the pressure at a point in a fluid depend on?
The depth and the density at that point
Why does some objects sink?
If its weight is greater than the upthrust on it when fully immersed.
