Kinematic Formulae (A Formula Is a Mathematical Representation of a Relationship

Principles, Relationships and Ideas Covered So Far This Year Physics 1st Qtr 2009 Kinematic Formulae (A formula is a mathematical representation of a relationship.)

Coefficient of Friction µ = Ff/FN µ = coefficient of friction Ff = force of friction FN = force normal to surface, [normal in physics means perpendicular.]

Velocity vav = Δd/Δtand vav = (vf – vi)/2 vav = average velocity t = elapsed time d = position

Acceleration aav = (vf – vi)/Δt also written vf = vi - aavΔt aav = average acceleration vf = final velocity vi = initial velocity Δt = elapsed time

2 2 2 Displacement d = viΔt + 0.5 ac(Δt) and vf = vi - 2aavd and d = vavΔt d = displacement vi = initial velocity ac = constant acceleration Δt = elapsed time vf = final velocity

Force F = ma and W = mg F = force W = force due to gravity m = mass a = acceleration g = acceleration due to gravity

You can use any of the formulae above to talk about how one value changes in response to another. Do you want to increase force? What has to get bigger? Which one can you control?

Introduction to Physics - Handout with definitions like Frame of Reference What part of an action are you focusing on? How many objects and/or motions are in your frame?

Chapter 3 – Describing Motion - Newton’s Laws 1. An object in motion tends to stay in motion, and object at rest tends to stay at rest unless acted on by an outside, unbalanced force. (inertia – measured in kg) Corollary: An object with no net force acting on it will move at a constant velocity (which may be zero). 2. Force = Mass x Acceleration 3. For every action there is an opposite and equal reaction Principles, Relationships and Ideas Covered So Far This Year Physics 1st Qtr 2009 Chapter 3 – Describing Motion (cont’d) - Definitions Mass - the amount of matter in an object, or better the measure of inertia (quantifying a tendency) Inertia - (Newton’s first law) a tendency Momentum - mass time velocity (how inertia changes with speed) Weight - the amount of gravitational force exerted on an object by a massive body (like earth) Chapter 5 – Forces Handout naming different forces, their types and what they mean Know what all the symbols mean in the formulae above. Know what is being described and their relationships. Name the forces at work in your sport and their directions. Where is the origin of the motions you are describing?

Other ideas may be found in your text and in chapter summaries on pages 54 and 91.

You may discuss what you have learned in class from videos, experts, research on various forces involved in your sport, gravity, center of balance, center of gravity, aero or fluid dynamics, speed, projectile motion, and other topics.

You’ve been doing word problems applying these principles and relationships to fictional situations. Now you are going to be graded on your ability to apply these principles and relationships to your sport.