Physics of Fluids and Machines

Flashcards covering the physics of fluids (Pascal's Principle), simple vs. compound machines, and mechanical efficiency.

How is Pressure ($P$) mathematically defined in the notes?

$P = \frac{F}{A}$ where $F$ is Force in Newtons and $A$ is Area in square meters.

What is the standard unit of pressure and its equivalent in Newtons per square meter?

The Pascal $(Pa)$, where $1\,Pa = 1\,N/m^2$.

State Pascal's Principle (1647).

Pressure applied to an enclosed fluid is transmitted undiminished to every portion of the fluid and acts equally in all directions.

What property of fluids is necessary for Pascal's Principle to work effectively, unlike with gases?

The fluid must be incompressible so that volumes cannot squeeze closer together.

How does a hydraulic system multiply force?

By pushing fluid from a small input piston into a larger cylinder, which allows a small effort to lift massive weights.

What is the primary difference in force response between Sand and a Bed of Nails?

In sand, the force travels in one direction (straight down), while a bed of nails (fluid response) turns force into pressure that shoots out in every direction at once with equal intensity.

What is the definition of a simple machine?

A mechanical device that changes the direction or magnitude of a force using a single, basic mechanism.

List the six types of simple machines mentioned in the notes.

Lever, Wheel & Axle, Pulley, Wedge, Inclined Plane, and Screw.

Identify which simple machines are categorised as 'Translational' and which are 'Rotational'.

Translational: Wedge, Inclined Plane, and Screw. Rotational: Lever, Wheel & Axle, and Pulley.

What is a compound machine?

A device made of two or more simple machines combined to accommodate complex tasks.

Give three examples of compound machines provided in the transcript.

A bicycle, scissors, and a can opener.

What are the specific components of a bicycle as a compound machine?

Pedals (Wheel & Axle), Gears & Chain, and the Rear Wheel.

How is 'Torque' defined in the lecture notes?

Rotational force, or "force w/ a handle."

Why are machines never 100% efficient?

Because of output work loss due to sound energy, heat energy, and friction.

What are two ways to improve machine efficiency mentioned in the notes?

Lubrication and using bearings to reduce friction.

Name two everyday conveniences that use hydraulic or pneumatic fluid cylinders.

Barber Chairs and Office Chairs.

How do automotive brakes use the Pascal Concept?

Pressing the brake pedal forces fluid through lines to squeeze calipers against the wheels to stop the car.

Define 'Tension' as per the forces acting on a machine.

A pulling force.