Kinematics: How things move! Velocity and Acceleration.

Slides:



Advertisements
Similar presentations
Chapter 2. Concepts of Motion
Advertisements

PHYSICAL SCIENCE MOTION
Kinematics – Defining Motion
Displacement and Velocity
Kinematics Goals: understand graphs of a) position versus time, b) velocity versus time.
Linear Motion 1 Aristotle 384 B.C B.C. Galileo
Linear Motion 1 Aristotle  384 B.C B.C. Galileo 
SPEED AND VELOCITY NOTES
8.1 The Language of Motion Some common words used to describe motion include: Some common words used to describe motion include: –Distance –Time –Speed.
Chapter 2 Preview Objectives One Dimensional Motion Displacement
Kinematics: Motion in One Dimension
Physics Ch. 3 Position, Speed, and Velocity
Kinematics Vector and Scalar Definitions Scalar: a physical quantity that can be defined by magnitude (size) only. Vector: a physical quantity that can.
Speed ( ) is the distance an object travels divided by the time to travel that distance. In other words –Speed is a scalar quantity (no direction). These.
Usain Bolt is the world’s fastest man!!!. Physics of Motion We will look at: –Distance –Displacement –Speed First you need to realize that motion is relative…
UNIT #3 – CHAPTER #8.2 – AVERAGE VELOCITY. Objectives  Be able to calculate average velocity, displacement, and time interval for an object in uniform.
Motion in One Dimension Kinematics. Distance vs. Displacement Distance – how far you’ve traveled Scalar quantity - 20 m Displacement – shortest distance.
Chapter 2 Describing Motion: Kinematics in One Dimension.
Ch 2 Velocity ~Motion in One Dimension~. Scalar versus Vector Scalar – quantity that only has magnitude –In the previous slide, which is the scalar? Vector.
Motion in One Direction Chapter : Displacement and Velocity Main Objectives:  Describe motion in terms of frame of reference, displacement, time,
Ch. 2: Describing Motion: Kinematics in One Dimension.
Chapter 2, Kinematics. Terminology Mechanics = Study of objects in motion. –2 parts to mechanics. Kinematics = Description of HOW objects move. –Chapters.
Chapter 3 Kinematics in Two Dimensions; Vectors. Units of Chapter 3 Vectors and Scalars Addition of Vectors – Graphical Methods Subtraction of Vectors,
Aim: How can we distinguish between a vector and scalar quantity? Do Now: What is the distance from A to B? Describe how a helicopter would know how to.
Ch. 2: Describing Motion: Kinematics in One Dimension.
DESCRIBING MOTION: Kinematics in One Dimension CHAPTER 2.
A 25kg block slides down a 20 degree ramp. What is the normal force? A N B. 230 N C. 245 N D N.
MOTION IN ONE-DIRECTION: DISPLACEMENT, VELOCITY, & ACCELERATION PHYSICS.
Ch. 2: Describing Motion: Kinematics in One Dimension.
Chapter 2 Motion Along a Line. MFMcGraw- PHY 1410Ch_02b-Revised 5/31/20102 Motion Along a Line Position & Displacement Speed & Velocity Acceleration Describing.
Physics Physics is the most basic of the sciences. It is the study of forces, motion, light, heat, sound, energy, matter, atomic and subatomic structure.
Kinematics in Two Dimensions AP Physics 1. Cartesian Coordinates When we describe motion, we commonly use the Cartesian plane in order to identify an.
Chapter 2: Motion, Forces, & Newton’s Laws. Brief Overview of the Course “Point” Particles & Large Masses Translational Motion = Straight line motion.
Speed ( ) is the distance an object travels divided by the time to travel that distance. In other words –Speed is a scalar quantity (no direction). These.
Describing Motion with Words
Do Now Time (sec.) Position (meters) )Calculate the average speed.
Introduction to One- Dimensional Motion. Quantities associated with motion Scalar Quantities do not have direction. Scalar quantities only have magnitude.
Velocity is a vector quantity therefore must include direction.
Introduction to Kinematics Vectors, Scalars, and Motion!
Speed ( ) is the distance an object travels divided by the time to travel that distance. In other words –Speed is a scalar quantity (no direction). These.
Kinematics: Intro Physic 11. What is kinematics?  area of Physics  Is the branch of mechanics concerned with motion without reference to force or mass.
What is Motion??? Motion—the movement of an object in relation to frame of reference.
Kinematics Kinematics is the branch of physics that describes the motion of points, bodies (objects) and systems of bodies (groups of objects) without.
Vectors.
Kinematics Descriptions of Motion aka “Kinematics” time ( t ) position (d)  displacement (  d) velocity (v) acceleration (a)
Chapter 2: Linear Motion Kinematics. Kinematics Kinematics is the science of describing the motion of objects using words, diagrams, numbers, graphs,
Kinematics – the study of the motion of objects without consideration to mass or the forces acting upon objects.
Motion, Speed, & Velocity. Motion Motion is a change in position (relative to a reference point) *reference point- stationary (still) object.
Unit 1: Motion and its Applications Kinematics. the language of motion mechanics  the study of objects in motion dynamics  the study of why things move.
(c) McGraw Hill Ryerson Average Velocity Pages 362 – 375 Words to Know:  average velocity  Speed  Velocity.
Motion in One Dimension Mechanics – study of the motion of objects and the related concepts of force and energy. Dynamics – deals with why objects move.
Unit B 1.2 Velocity. Velocity Describes both the rate of motion and the direction of an object You can determine the speed of a car by looking at the.
Introduction to Motion
B1.2 Velocity.
Force and Motion. Prior Concepts Related to Forces PreK-2 Forces are pushes and pulls that change the motion of an object. Forces are required to change.
Advanced Physics Chapter 2 Describing Motion: Kinematics in One Dimension.
Motion in One Dimension - velocity. Motion – A change in position Motion.
Speed Velocity and Acceleration. What is the difference between speed and velocity? Speed is a measure of distance over time while velocity is a measure.
Mechanics The study of Physics begins with mechanics. Mechanics is the branch of physics that focuses on the motion of objects and the forces that cause.
Ch. 8.2 Average Velocity Speed ( ) is the distance an object travels divided by the time to travel that distance. In other words Speed is a scalar quantity.
Ch. 8.2 Average Velocity Speed ( ) is the distance an object travels divided by the time to travel that distance. In other words Speed is a scalar quantity.
Introduction to Kinematics
Uniform Motion.
Ch. 8.2 Average Velocity Speed ( ) is the distance an object travels divided by the time to travel that distance. In other words Speed is a scalar quantity.
Introduction to Kinematics
Mechanics The study of Physics begins with mechanics.
Motion in 1D, Vectors and Velocity
Kinematics.
Describing Motion: Kinematics in One Dimension
Kinematics: Displacement and Velocity
Presentation transcript:

Kinematics: How things move! Velocity and Acceleration

Motion: Kinematics The study of motion is known in the physics world as kinematics. Kinematics describes motion by using words, diagrams, numbers, graphs and equations. Vectors, scalars, distance, displacement, speed, velocity and acceleration are all words often used to describe the motion of objects. The study of motion is known in the physics world as kinematics. Kinematics describes motion by using words, diagrams, numbers, graphs and equations. Vectors, scalars, distance, displacement, speed, velocity and acceleration are all words often used to describe the motion of objects.

Kinematics is concerned with the motions of objects without being concerned about what causes the motion. We'll only touch motion in one dimension for this unit and leave two dimensions for later Kinematics is concerned with the motions of objects without being concerned about what causes the motion. We'll only touch motion in one dimension for this unit and leave two dimensions for later

Frame of Reference An important concept we need for talking about the motion of object is the one of 'frame of reference'. When you are on the school bus, the person sitting in front of you is not moving when compared to you. When you look out the window at the road it is obvious that you are moving with respect to it. What is different in each case is the frame of reference. An important concept we need for talking about the motion of object is the one of 'frame of reference'. When you are on the school bus, the person sitting in front of you is not moving when compared to you. When you look out the window at the road it is obvious that you are moving with respect to it. What is different in each case is the frame of reference.

Now before we can really talk about moving from place to place we need to be able to describe where exactly we are at any time. This is known as position. In order to describe positions we need a reference point Now before we can really talk about moving from place to place we need to be able to describe where exactly we are at any time. This is known as position. In order to describe positions we need a reference point The reference point can be anywhere you wish it to be. We usually place it somewhere to make the math easy. The best spots are usually the starting point of your trip, ground level etc. The reference point can be anywhere you wish it to be. We usually place it somewhere to make the math easy. The best spots are usually the starting point of your trip, ground level etc.

Here are two examples involving a well. Notice how the values of the y-positions change as we change the reference point (zero line).

Example 1 -The reference point (zero line) is placed at 'ground' level. -Positions of the ball below the zero line are negative. -Positions of the ball above the zero line are positive.

Example 2 - The reference point (zero line) is placed at the lowest point. - All positions of the ball are positive

Usually when talking about direction, up, north, east and right indicate positive directions and down, south, west and left indicate negative directions. Usually when talking about direction, up, north, east and right indicate positive directions and down, south, west and left indicate negative directions. Regardless of where we place the reference point, the change in any two positions in either picture above is always the same. In both cases you should find that the change is 20 m. This idea is true in a any situation. Regardless of where we place the reference point, the change in any two positions in either picture above is always the same. In both cases you should find that the change is 20 m. This idea is true in a any situation.

Vectors and Scalars A study of motion will involve the introduction of a variety of quantities which are used to describe the physical world. Examples of such quantities include distance, displacement, speed, velocity, acceleration, force, mass, momentum, energy, work, power, etc. All these quantities can be divided into two categories - vectors and scalars. A study of motion will involve the introduction of a variety of quantities which are used to describe the physical world. Examples of such quantities include distance, displacement, speed, velocity, acceleration, force, mass, momentum, energy, work, power, etc. All these quantities can be divided into two categories - vectors and scalars.

SCALARS SCALARS Scalars can be completely described by a magnitude value. Scalars can be completely described by a magnitude value. VECTORS VECTORS A vector quantity is described completely only if both its magnitude and direction are described

Scalar vrs. Vector Distance Distance 15 km15 km Speed Speed 30 m/s30 m/s Time Time 10s10s Mass Mass 6 kg6 kg Displacement Displacement 15 km [N 45 E] Velocity Velocity 30 m/s [S] Acceleration Acceleration 9.81 m/s [down]

Motion Terms Position Position Locates an object within the frame of referenceLocates an object within the frame of reference symbol: dsymbol: d Indicates location of object from the reference point. It is possible to have a negative valueIndicates location of object from the reference point. It is possible to have a negative value Displacement Displacement Symbol: ΔdSymbol: Δd The distance from an initial position to the finishing positionThe distance from an initial position to the finishing position Δd = d f – d iΔd = d f – d i This change in position is actually given its own name. It is called the displacement. It is different than what we usually call distance. With distance we don't care where the reference point is but with displacement we do. This change in position is actually given its own name. It is called the displacement. It is different than what we usually call distance. With distance we don't care where the reference point is but with displacement we do.

Displacement and Velocity Diagrams allow you to describe motion qualitatively. We describe motion quantitatively by taking measurements Diagrams allow you to describe motion qualitatively. We describe motion quantitatively by taking measurements Two fundamental measurements involved in motion are distance and time. Using this you can calculate an object’s position, speed and rate of change of speed at any particular time Two fundamental measurements involved in motion are distance and time. Using this you can calculate an object’s position, speed and rate of change of speed at any particular time

Displacement Problem A squirrel starts at the curb and tries to scamper straight across a road. It runs out 8 m, sees a dog on the other side of the road and runs back 3 m before being flattened by a truck. What was the squirrel's displacement? A squirrel starts at the curb and tries to scamper straight across a road. It runs out 8 m, sees a dog on the other side of the road and runs back 3 m before being flattened by a truck. What was the squirrel's displacement?

Displacement Solution reference point: the starting point of the trip. This is why I've labelled the starting curb as x=0. The squirrel starts at the curb (x1) and 'finishes' at x2. We know that x1=0 since that is our zero line so we just need the value of x2. A little inspection should reveal that x2=5 m. The squirrel's displacement is then reference point: the starting point of the trip. This is why I've labelled the starting curb as x=0. The squirrel starts at the curb (x1) and 'finishes' at x2. We know that x1=0 since that is our zero line so we just need the value of x2. A little inspection should reveal that x2=5 m. The squirrel's displacement is then (No squirrels were harmed in the construction of this example.) (No squirrels were harmed in the construction of this example.)

Example 2 While waiting for someone I pace 5 m east, 4 m west, another 2 m west, and 3 m east. What was my displacement from my starting point? While waiting for someone I pace 5 m east, 4 m west, another 2 m west, and 3 m east. What was my displacement from my starting point?

Time and Time Intervals Time and Time Intervals The elapsed time between two instantsThe elapsed time between two instants Velocity Velocity Scalar - SpeedScalar - Speed Distance travelled divided by the time spent travelling Distance travelled divided by the time spent travelling Speed = distance /time Speed = distance /time Vector – VelocityVector – Velocity How fast the object is moving including the direction How fast the object is moving including the direction Rate of change in position Rate of change in position Average velocity = displacement /time Average velocity = displacement /time