SCIENCE12 Physics ATAR: Motion

Principles and Laws of Motion

This programme looks at some of the major principles and laws relating to motion, and uses a range of everyday examples of motion to explore how these principles and laws play out.

Source: ClickView, Classroom Video, 2009, Rated E, Duration 18:50, URL: https://svacs.libapps.com/libguides/admin_c.php?g=939950&p=6865297

Newton's Laws: Crash Course Physics #5

What do Isaac Newton's laws mean? And how do they help us understand the world around us?

Source: YouTube, CrashCourse, Duration 11:03, URL: https://www.youtube.com/watch?v=kKKM8Y-u7ds

Law of Universal Gravitation equation

meriSTEM Gravitation and Motion will take you through the Law of universal gravitation, projectile motion, uniform circular motion, orbits, gravitational fields and introduce general relativity.

Source: ClickView, 2020, Rated G, Duration 1:24, URL: https://online.clickview.com.au/exchange/videos/22982252/1-5-law-of-universal-gravitation-equation

Gravity and motion

This clip explains, both qualitatively and quantitatively, the law of gravitation, and how Newton’s second and third laws of motion come into play when explaining the integral part that gravity plays in universal physical phenomena. It is an ideal resource for senior level students of physics.

Source: ClickView, 2017, Rated E, Duration 8:57, URL: https://online.clickview.com.au/libraries/videos/5373883/newton-s-laws-of-gravitation-and-motion

In vertical circular motion the speed, as well as the direction of the object, is constantly changing. Gravity is constantly either speeding up the object as it falls, or slowing the object down as it rises.

Circular motion (Power Point)

Source: Slide ToDoc, URL: https://slidetodoc.com/circular-motion-objective-define-circular-motion-define-angular/

Amusement Park Physics

A great resource for all things physics. This link includes the clothoid loops (that we will approximate as a circle), the sharp 180-degree banked turns, and the small dips and hills found along otherwise straight sections of the track.

Source: the Physics Classroom, URL: https://www.physicsclassroom.com/Class/circles/u6l2b.cfm

A banked curve is a curve that has its surface at angle with respect to the ground on which the curve is positioned. The reason for banking curves is to decrease the moving object's reliance on the force of friction.

Source: PowerPoint Presentation, URL: http://www.sfu.ca/~mxchen/phys1011101/Lecture06B.pdf

A fictitious force is a force that appears to act on a mass whose motion is described using a non-inertial frame of reference, such as an accelerating or rotating reference frame.

Source: Wikipedia, Fictitious force, 2021, URL: https://en.wikipedia.org/wiki/Fictitious_force

Projectile motion is the motion of an object thrown or projected into the air, subject to only the acceleration of gravity. 

Source: Lumen Learning, URL: https://courses.lumenlearning.com/physics/chapter/3-4-projectile-motion/

Equations of motion

Equations of motion relate the displacement of an object with its velocity, acceleration and time. 

For a constant acceleration a, an initial speed u, and an initial position of zero:

  Average velocity                                                                                           

Source: Isaac Physics (University of Cambridge), URL: https://isaacphysics.org/concepts/cp_eq_of_motion?stage=all

Air resistance and projectile motion

Factors affecting trajectory:

Air resistance

As a projectile moves through the air it is slowed down by air resistance. Air resistance will decrease the horizontal component of a projectile. The effect of air resistance is very small, but needs to be considered if you want to increase the horizontal component of a projectile.

There are several factors that relate to the amount of air resistance acting on a projectile.

1. Surface to volume ratio. The larger the surface to volume ratio, the more air resistance will affect the object. For example, a badminton shuttle will have much more air resistance than a golf ball, because of the holes in it.
2. The surface of the object. If the surface is rough, the air resistance will be greater.
3. Speed. As speed increases, so does air resistance. This is because of friction, for example a space shuttle.
4. Mass. The smaller the mass of an object, the more air resistance will affect it. For example a feather, compared to a stone.

Because air resistance affects the horizontal component of a projectiles trajectory, the effect of it can be minimized by lowering the angle of release.

Source: Principles of projection motion posters [Word Doc.]

Projectile Motion Interactive

Determine how each parameter (initial height, initial angle, initial speed, mass, diameter, and altitude) affects the trajectory of an object, with and without air resistance.

Source: PhET Interactive Simulations (University of Colorado), 2021, URL: https://phet.colorado.edu/sims/html/projectile-motion/latest/projectile-motion_en.html

Uniform circular motion can be described as the motion of an object in a circle at a constant speed. As an object moves in a circle, it is constantly changing its direction. At all instances, the object is moving tangent to the circle.

Source: the Physics Classroom, URL: https://www.physicsclassroom.com/mmedia/circmot/ucm.cfm

Uniform circular motion equations

Source: Study.com, URL: https://study.com/cimages/multimages/16/392ded2b-299e-4aaf-8af2-a2185da91322_equations.jpg

Mathematics of circular motion

The Mathematics of Circular Motion Video Tutorial describes the equations that can be used to determine the speed, acceleration, and net force experienced by objects moving in circles. Five examples of the use of the equations are discussed.

Source: the Physics Classroom, URL: https://www.physicsclassroom.com/Physics-Video-Tutorial/Circular-Motion-and-Gravitation/Mathematics-of-Circular-Motion/Video

Uniform circular motion

When an object moves along a circular path at a constant speed, its motion is called uniform circular motion.

Source: ClickView, 2019, Rated E, Duration 6:46, URL: https://online.clickview.com.au/libraries/videos/31686585/uniform-circular-motion

Orbits of satellites

Constant unbalanced forces, known as centripetal forces, cause planets, moons and stars in the universe to orbit one another. This clip, aimed at senior level students of physics, examines fundamental aspects of orbital motion of satellites in our solar system and beyond, including physical quantities affecting orbital motion, Kepler’s laws of planetary motion and orbital properties and their uses.

Source: ClickView, 2017, Rated E, Duration 12:53, URL: https://online.clickview.com.au/libraries/videos/5428721/orbits-of-satellites

The centripetal force requirement

The Centripetal Force Requirement Video Tutorial explains what is meant by a centripetal force and why a centripetal force is required to sustain a circular motion.

Source: the Physics Classroom, URL: https://www.physicsclassroom.com/Physics-Video-Tutorial/Circular-Motion-and-Gravitation/Centripetal-Force-Requirement/Video