Unit 6 Competency 2 - Explore mechanisms and simple machines to create working robots

Suggested Objective a: Define and describe principles relating to Newton’s Laws of Motion

Sir Isaac Newton had three laws of motion. They are as follows:

An object at rest will remain at rest unless acted on by an unbalanced force.

Acceleration is produced when a force acts on a mass.

For every action there is an equal and opposition reaction.

You can learn more about these laws by vising the Rice website. Links to an external site. Click the links to learn more about the laws of motion. There is a quiz to guide you with checking your understanding of the material presented.

Newton's 3 (three) Laws of Motion Links to an external site.

Newton's First Law of Motion Links to an external site.

Newton's Second Law of Motion Links to an external site.

Newton's Third Law of Motion Links to an external site.

Motion

What is motion? According to Webster: an act or process of moving. In physics and engineering, we say motion is a change in position of an object with respect to time and its reference point. We can describe motion using words, graphs, and equations.

Newton's Laws of Motion

There are three laws governing motion, by Sir Isaac Newton.

Newton's First Law Links to an external site. is also known as the Law of Inertia. The first law states:

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Let's think about what the first law is describing. It's talking about two states that an object can be in: at rest and in motion The diagram below pictorally represents Newton's First Law.

balanced clause.gif

Newton's Second Law Links to an external site. is also known as the acceleration law. The second law states:

F = ma. The vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration vector a of the object.

Let's examine the second law further. If we solve for acceleration, we have a = F/m. This is stating the acceleration is directly proportional to the force and inversely proportional to the mass of an object. This makes sense because more massive objects require more force to move the same distance as less massive objects.

Newton's Third Law Links to an external site. is known as the action/reaction law. The third law states:

For every action, there is an equal and opposite reaction.

References:

You can follow this link to the Physics Classroom for a more information on Newton's Laws.

*Some of this page was adapted from www.thephysicsclassroom.com Links to an external site.

Machines and Mechanisms

What is a machine? Watch this video Links to an external site. from Bil Nye the Science Guy to deepen your understanding.

What is a mechanism? A mechanism is a system that transforms one kind of motion to another, and may consist of a single component or a combination of the fundamental components: lever, cam, screw, pulley, gear or ratchet.

Suggested Objective b: Distinguish the principles of physics involved in gears and gear trains

BowlesPhysics.com Links to an external site. posted a PowerPoint about gears. Please look at the PowerPoint to see what gears are, the purpose of gears, and types of gears and gear systems. Take notes as you progress through the PowerPoint. Feel free to download the pdf that was found December 8, 2014. http://bowlesphysics.com/images/Robotics_-_Gears_and_Gear_Ratios.pdf Links to an external site.

ScienceKids Links to an external site.has a video to gears posted. An explanation is provided for what gears are. http://www.sciencekids.co.nz/videos/physics/gears.html Links to an external site.

How Gears Work Links to an external site. from How Stuff Works provides an explanation and video to gears. Additional links for information on gears are given. Check out this info! http://science.howstuffworks.com/transport/engines-equipment/gear.htm Links to an external site.

Gear Basics Links to an external site.

Gear and Wheels Part 1 Links to an external site.

Gear Trains (Part 1) Links to an external site.

Suggested Objective c: Recognize fundamentals of rotational dynamics, torque, motors, and angular velocity