Question

year 9 physics homework 6: fluids and pressure
due date

question 1: the basics of pressure

1. definitions & units

a. define \fluid pressure\ in terms of weight and surface area.

b. complete the table for p=f/a
\

$$\begin{tabular}{|l|l|l|l|} \\hline variable & symbol & unit & unit symbol \\\\ \\hline & & & pa \\\\ \\hline & & newtons & \\\\ \\hline & a & & \\\\ \\hline \\end{tabular}$$

c. if a force of 100n is applied over an area of \\(2\text{m}^2\\), calculate the pressure in this unit.

1. historical context

research task: briefly explain \pascals principle\ regarding how pressure is transmitted through a confined fluid.

question 2: atmospheric pressure

1. altitude & weight

as a climber ascends (goes up) mount everest the air becomes \thinner\ and the pressure decreases as they climb higher.
explain why the pressures decreases. refer to the \weight of the air column\ in your answer.

Explanation:

Define fluid pressure

Fluid pressure is defined as the force exerted by the weight of a fluid per unit of surface area.

$$ P = \frac{F}{A} $$

Complete the variable table

We identify the three variables in the formula \(P = F/A\):

• Row 1: The unit symbol is \(\text{Pa}\) (Pascals), which corresponds to the variable Pressure, represented by the symbol \(P\), with the unit Pascals.
• Row 2: The unit is Newtons, which corresponds to the variable Force, represented by the symbol \(F\), with the unit symbol \(\text{N}\).
• Row 3: The symbol is \(A\), which corresponds to the variable Area, with the unit Square meters and unit symbol \(\text{m}^2\).

Calculate pressure from force and area

Using the given values:

• Force \(F = 100\text{ N}\)
• Area \(A = 2\text{ m}^2\)

We apply the pressure formula:

$$ P = \frac{F}{A} = \frac{100\text{ N}}{2\text{ m}^2} = 50\text{ Pa} $$

Explain Pascal's Principle

Pascal's Principle states that any change in pressure applied to an enclosed fluid is transmitted undiminished throughout the fluid to all parts of the fluid and the walls of its container.

Explain atmospheric pressure decrease with altitude

As a climber ascends, the height of the air column directly above them decreases. Since there is less air above, the total weight of the air column pressing down on a unit area is reduced, resulting in lower atmospheric pressure.

Answer:

Question 1a

Fluid pressure is the force exerted by the weight of a fluid per unit of surface area.

Question 1b

Variable	Symbol	Unit	Unit Symbol
Force	\(F\)	Newtons	\(\text{N}\)
Area	\(A\)	Square meters	\(\text{m}^2\)

Question 1c

\(50\text{ Pa}\)

Question 2

Pascal's Principle states that pressure applied to a confined fluid is transmitted equally and undiminished in all directions throughout the fluid.

Question 3

As altitude increases, the height and density of the air column above the climber decrease. This reduces the total weight of the air column pressing down per unit area, causing atmospheric pressure to decrease.