Week 5

What other simple machines are there?

learning intentions

To recognise different classes of leavers and their roles as force and distance magnifiers
Explore the mechanical advantage levers and incline planes.

Tasks

Knowledge & understanding

Finish the Mechanical Advantage worksheet on Google Classrooms
CK12 - Wedge, Screw, Wheel & Axle

Investigation Skills

Prac: Investigating Friction

Literacy & research

Why does a boomerang fly - annotated drawing on Google Classrooms

Knowledge and understanding

Mechanical advantage - review

Mechanical advantage refers to the measurement of the amplification of force achieved by using a simple machine, such as a lever, pulley, inclined plane, wheel and axle, or screw, to transmit or modify the application of force. It is the ratio of the output force produced by a machine to the input force applied to it. Essentially, it quantifies how much a simple machine multiplies or amplifies the input force to provide a greater output force, making it easier to perform a particular task or overcome a resistance. Mechanical advantage allows us to understand and quantify the efficiency and effectiveness of various simple machines in performing work.

The formula for mechanical advantage (MA) varies depending on the type of simple machine being used. Here are the formulas for some common types of simple machines:

Lever:

Mechanical Advantage (MA) = length of the load arm

length of the effort Arm

In your experiments you can measure and calculate mechanical advantage:

MA = Load Forces Load forces need to be calculated. Weight is a force, and measured in Newtons.

Effort Forces It is calculated by multiplying mass in kg x acceleration due to gravity (9.8 m/s/s)

Inclined Plane:

Mechanical Advantage (MA) = Length of Slope

Height of Slope

And for the sake of completion I will include how mechanical advantage is calculated for other types of simple machines, although you don't

Pulley:

For a single fixed pulley, the mechanical advantage is always 1.

For a system involving multiple pulleys or a movable pulley, the formula is:

MA = Count of Rope Segments Supporting the Load

Wheel and Axle:

Mechanical Advantage (MA) = Radius of Wheel

Radius of Axle

Screw:

Mechanical Advantage (MA) = 2 π Radius of the Screw

Pitch of the Screw

More Simple Machines

Double the Slope, Double the Power: Wedges as Twin Inclined Planes?

Think of a wedge as two inclined planes back-to-back, meeting at a point. This powerful pairing takes the same force-spreading magic of an inclined plane and doubles it, creating a tool that can slice or split with remarkable efficiency. Instead of lifting an object up a slope, the twin slopes of a wedge work together to drive materials apart, converting a small input force at its top into a powerful outward push on either side. With this clever setup, the wedge becomes a simple yet highly effective machine for tasks like cutting and splitting.

The Twisting Ramp: How Screws Spiral into Simple Machines

Picture an inclined plane wrapped around a cylinder—that’s a screw! By twisting the ramp into a spiral, the screw turns a simple slope into a powerful tool for holding objects together or lifting loads. Just like an inclined plane, the screw spreads the applied force over a distance, but its spiral shape means that even a small rotational force can translate into a large forward push. With each twist, the screw’s threads drive deeper or lift heavier, making it essential for construction, fastening, and even mechanical movement.

Turning Together: The Power of the Wheel and Axle

A wheel and axle is a simple machine that harnesses the power of rotation by combining two connected rings or cylinders, one inside the other, turning around a single center point. When a force is applied to the larger wheel, it makes it easier to turn the smaller axle, amplifying the force and creating a mechanical advantage greater than 1—ideal for lifting or pulling heavy loads, like in pulleys or winches. On the other hand, applying force to the axle makes the wheel spin faster, producing a mechanical advantage of less than 1, useful for gaining speed, as seen in bicycles and cars. This versatile machine shows how simple rotation can turn small inputs into powerful effects, adapting to different tasks by where you apply the force.

Investigation skills

Prac: Investigating Friction

When do you use bar charts and when do you use a scatter plot with a trend line?

Bar charts are used to display and compare discrete categories of data, such as different types of fruits or favourite colours. They are helpful for showing and comparing data that do not have a natural order or progression. We call this non-continuous data as it consists of distinct categories and cannot be measured.

On the other hand, line charts are used to illustrate trends and changes over time or to show the relationship between two continuous variables, like temperature over the course of a week. We call this continuous data.

When we are looking at different surface types such as carpet, wood, sand paper etc, do you think this is continuous or non-continuous data? Should we use a bar chart or a line chart?

Literacy & research

Why a boomerang flies?

Why a Boomerang fliesThe vital boomerang attributes: convex top surface, distinctive curve, thin body and wide surface area are essential to the boomerang's aerodynamic properties.

Read the text then answer the questions:

What is a ballistic missile?
In what way is the boomerang an example of a non-ballistic missile?
What attributes of a boomerang are essential for it's aerodynamic qualities?
What characteristics of a boomerang mean it can resist the force of gravity and stay in the air?

Create an annotated drawing and explaination of the aerodynamics of a boomerang. You may copy-paste images, but you must add text and annotate the image. Put your answer to the above questions on the drawing as well.

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