Exam Study Notes

Science: Social Systems vs. Physical Systems

Similarities

• Both can be either natural or human-made.

Differences

• Physical System: Relies on physical parts to function.
• Social System: Relies on a group of organisms that work together to function.

Types of Systems

Physical Systems

• Mechanical: Uses mechanical energy or pressurized air.
• Optical: Uses light energy.
• Electrical: Uses electrical energy.

Social Systems

• Aboriginal clans
• Education
• Healthcare
• Waste management

System Examples (Inputs and Outputs)

Physical System (Optical: Camera)

• Input: Light energy (Information it receives and processes).
• Output: Image/video.
• Side Effect: Some images/videos may appear distorted.

Social System (Natural: Wolfpack)

• Input: Communication, environmental conditions.
• Output: Cooperative hunting, food sharing.
• Side Effect: Territorial conflict, aggression.

System Inputs and Outputs

Inputs

• Everything that goes into a system to make it work (forces, raw materials, energy).

Outputs

• The task or service that the system performs.

Side Effects

• The unintended or undesired outputs of a system.

Examples

• Input: The input of a can opener is the force your hand applies on the handle.
• Output: The output of a can opener is the turning and cutting of the can’s lid.
• Side Effects: The side effects of a can opener are the risk of sharp edges on the can’s lid or the can itself.

System Thinking

Definition

• Thinking about how the parts of a system work together.

System Thinking Affecting Systems

• System thinking can help reduce side effects and reduce their negative effects on the environment and society.

Simple Systems

Definition

• A device that requires one force made up of 1-2 parts.

Types of Simple Systems

• Incline Plane: A tilted, flat surface.
• Wedge: A modified incline plane that moves back and forth.
• Screw: An incline plane cut into a central core.
• Lever: A rigid bar that pivots at the fulcrum.
• Wheel and Axle: A wheel that turns the axle; a small force becomes a larger force.
• Pulley: Using a wheel and axle to move items.
• Gear: A modified wheel and axle; toothed wheels are used to speed up or slow down motion.

Weight / Mass

Weight

• The force acting on an object.

Mass

• The amount of matter in an object.

Mass vs. Weight

Mechanical Advantage

Definition

• The ratio of output force to input force for a given machine.

Mechanical Advantage for Certain Machines (Examples)

Wheelbarrow

• Effort arm length: $120$ cm
• Load arm length: $40$ cm
• $MA = \frac{effort \, arm \, length}{load \, arm \, length} = \frac{120 \, cm}{40 \, cm}= 3$

Pulley

• Input distance: $15$ cm
• Output distance: $5$ cm
• $MA = \frac{input \, distance}{output \, distance} = \frac{15 \, cm}{5 \, cm} = 3$

Lever

• Input force: $25$ N
• Output force: $250$ N
• $MA = \frac{output \, force}{input \, force} = \frac{250 \, N}{25 \, N} = 10$

Difference Between MA of 2 and 5

MA 2

• Multiplies the force applied by 2.
• More force is required compared to MA 5.
• Moves a shorter distance.
• Faster output.

MA 5

• Multiplies the force applied by 5.

• Less force is required.

• Moves a longer distance.

• Slower output.

• MA 2 gives moderate force multiplication with less input distance.

• MA 5 gives more force multiplication, so you can lift heavier loads, but you must input more distance.

Third Class vs. First Class Levers

Third Class

• Input force is between the load force and the fulcrum.
• Input force is greater than output force.
• Increased distance and speed.
• MA is always less than 1.

First Class

• Fulcrum is between the load force and input force.
• MA can be greater than, less than, or equal to 1, depending on the distances.
• More force ($MA > 1$), equal force ($MA = 1$), or more effort ($MA < 1$).
• Output can be force, speed, and distance (Speed and distance is less compared to 3rd class).

Work

Formula

• $w = f \times d$
• Nm = Newton meters
• $1 \, Nm = 1 \, joule$

Work Done in a Plank Position

• In a plank position, neither the body nor the ground is moving. Even so, work is still being done.
• Energy is being consumed by the body working to maintain this position while being pulled down by gravity.

Application of Efficiency to a System

• Energy is always lost in systems, some more than others.
• Efficiency is making sure a desired outcome is achieved while losing minimal energy and effort.

Efficiency in Social Systems

• Economic Efficiency: Achieving a desired outcome without wasting energy, effort, or materials.