P5: PRESSURE

Question 1

What is the equation that links pressure, force and area?

Answer 1

pressure (Pa) = force (N) / area (m^2) (P = F/A)

Question 2

What is the equation for pressure in a liquid?

Answer 2

pressure (Pa) = height of column (m) x density of liquid (kg/m^3) x gravitational field strength (N/kg) (P = hρg)

Question 3

What causes objects to float in fluid?

Answer 3

if the upthrust is = to/larger than the objects weight, the object will float

Question 4

Why does atmospheric pressure decrease with increasing altitude?

Answer 4

-as altitude increases, the atmosphere gets less dense so there are fewer air molecules that are able to collide with the surface
-there are also fewer air molecules above a surface as height increases which means that the weight of the air above it (which contributes to atmospheric pressure) decreases with altitude