P11: Pressure and Surfaces Flashcards
What is the equation for pressure?
Pressure (Pa) = Force / Area
How is pressure caused?
Pressure is caused when objects exert forces on each other, or when a fluid exerts a force on an object in contact with it.
How does pressure change in the air?
Air molecules collide with surfaces and create pressure on them.
Atmospheric pressure decreases and density decreases as altitude increases as there are less air molecules so there is a smaller weight.
What is upthrust and how is it increased?
Upthrust is water exerting an upward force on an object in the water, caused by the pressure of a fluid.
The more an object is lowered into the water, the more volume displaced, resulting a greater upthrust and pressure. An object sinks if its weight is greater than its upthrust when fully immersed.
