Identical magnets are stuck at three radii on a rotating disc. The angular velocity of the disc is continually increased. What will happen to the magnets?

Slides:



Advertisements
Similar presentations
The Beginning of Modern Astronomy
Advertisements

Forces and Newton’s Laws. Force A force is what we call a push, or a pull, or any action that has the ability to change motion. There are two units of.
Forces in Motion. Galileo proved that the rate at which an object falls is not affected by the mass.
PHYS 218 sec Review Chap. 4 Newton’s laws of motion.
Chapter 6: Work & Energy. THE COURSE THEME is NEWTON’S LAWS OF MOTION! Chs. 4, 5: Motion analysis with forces. NOW (Ch. 6): An alternative analysis using.
AOSS 321, Winter 2009 Earth System Dynamics Lecture 6 & 7 1/27/2009 1/29/2009 Christiane Jablonowski Eric Hetland
Circular Motion and Other Applications of Newton’s Laws
< BackNext >PreviewMain Forces and Motion Preview Section 1 Gravity and MotionGravity and Motion Section 2 Newton’s Laws of MotionNewton’s Laws of Motion.
Circular Motion and Other Applications of Newton’s Laws
PHY131H1S - Class 17 Today: Review for Test 2!.
 Calculate the acceleration that this object experiences 30 kg 150 N.
Chapter everyday forces.
Chapter 5 More Applications of Newton’s Laws. Forces of Friction When an object is in motion on a surface or through a viscous medium, there will be a.
Chapter 3 Forces.
Motion occurs when an object changes position.
Chapter 3—Forces.
Universal Gravitation
S-24 Define the following terms A. Weight B. Gravity C. Friction
Unit 1 B Newton's Laws of Motion. 2 Classical Mechanics Describes the relationship between the motion of objects in our everyday world and the forces.
Chapter 4 Forces and the Laws of Motion. Newton’s First Law An object at rest remains at rest, and an object in motion continues in motion with constant.
Monday, Oct. 4, 2004PHYS , Fall 2004 Dr. Jaehoon Yu 1 1.Newton’s Law of Universal Gravitation 2.Kepler’s Laws 3.Motion in Accelerated Frames PHYS.
FORCES AND NEWTON’S LAWS
Resistance of an object to a change in its motion inertia.
Chapter 6 Circular Motion and Other Applications of Newton’s Laws.
Chapter 6 Circular Motion and Other Applications of Newton’s Laws.
More Applications of Newton’s Laws
1 5.2 Uniform Circular Motion A force,, is directed toward the center of the circle This force is associated with an acceleration, a c Applying Newton’s.
The Nature of Force Chapter 3 section 4 What is a force Force is a push or pull. Forces are either balanced or unbalanced.
 Extension of Circular Motion & Newton’s Laws Chapter 6 Mrs. Warren Kings High School.
1 Acceleration Is the change in speed or velocity with time for motion in a straight line so that a = ∆v/t The units are usually m/sec 2 In the equation,
Chapter: Force and Newton’s Laws
Force and Motion Part II Circular Dynamics February 15, 2006.
Chapter 7: Rotational Motion and the Law of Gravity Angular Speed & Acceleration  A unit of angular measure: radian y x P r  s = r  where s,r in m,
Circular Motion and Other Applications of Newton’s Laws
Forces and Motion. Forces Affect Motion /A force is a push or a pull that changes motion. /Forces transfer energy to an object. /The force of gravity.
CH 3 Forces. Sec 1 Newton’s 2 nd Law Net force acting on an object causes the object to accelerate in the direction of the net force Amount of “a” depends.
Force = a push or a pull Mrs. Clarici
Chapters 5, 6 Force and Laws of Motion. Newtonian mechanics Describes motion and interaction of objects Applicable for speeds much slower than the speed.
Chapter 6 Forces and Motion.
1 Newton’s Second Law: Motion in a Circle Readings: Chapter 8.
5.5 Non-uniform circular motion 5.6 Drag Velocity
Wednesday, Oct. 2, 2002PHYS , Fall 2002 Dr. Jaehoon Yu 1 PHYS 1443 – Section 003 Lecture #6 Wednesday, Oct. 2, 2002 Dr. Jaehoon Yu 1.Newton’s laws.
Forces & Motion. What is a Force? Force: push or pull Unit: Newton (N)  Kg x m/s 2 Vector: has both magnitude & direction.
Chapter 3 Forces. Section 1 Newton’s Second Law Force, Mass and Acceleration Compare hard thrown ball vs. gently tossed ball Compare hard thrown ball.
< BackNext >PreviewMain Gravity and Falling Objects Gravity and Acceleration Objects fall to the ground at the same rate because the acceleration due to.
FORCE. Any push or pull Has two components: magnitude and direction Force is a quantity capable of changing the size, shape, or motion of an object SI.
Gravity Chapter Gravity Law of Universal Gravitation- all objects in the universe attract each other through gravitational force Law of Universal.
Chapter 3. Force, Mass, and Acceleration Newton’s first law of motion states that the motion of an object changes only if an unbalanced force acts on.
MOTION. Motion – the act or process of an object changing position. How do we know when an object has moved? After we have observed it for a given time,
Today's Concepts: Newton’s Laws a) Acceleration is caused by forces b) Force changes momentum c) Forces always come in pairs d) Good reference frames Physics.
Describing and Measuring Motion Are you in motion right now? Motion: an object is in motion if the distance from another object is changing.
Resources Section 1 Laws of Motion Objectives Identify the law that says that objects change their motion only when a net force is applied. Relate the.
A. Newton’s Laws Sir Isaac Newton (1642–1727)  able to state rules that describe the effects of forces on the motion of objects I. The First 2 Laws of.
Physical Science Chapter Four Acceleration Momentum Newton Gravity Free Fall Air Resistance.
PHY 151: Lecture Extending Particle in Uniform Circular Motion Model (Continued) 6.4 Nonuniform Circular Motion 6.5 Motion in Accelerated Frames.
Force and Motion–I Chapter 5. Newton's First and Second Laws A force: o Is a “push or pull” acting on an object o Causes acceleration We will focus on.
Forces. GPS Standards S8P3: Students will investigate the relationship between force, mass, and the motion of objects. a. Determine the relationship between.
The Nature of Force and Motion 1.Force – A push or a pull – How strong it is and in what direction? 2.Net Force – The sum of all forces acting on an object.
Acceleration & Momentum. Newton’s 2 nd Law of Motion states “a net force acting on an object causes an object to accelerate in the direction of the force”
Forces Chapter 3.
Chapter 8 Forces & Motion.
Circular Motion and Other Applications of Newton’s Laws
Forces.
Circular Motion and Other Applications of Newton’s Laws
FORCE and MOTION REVIEW
Chapter 10 Vocab Review 8th Grade.
Forces & Motion.
Chunk 5 Application of Newton’s Laws
Circular Motion and Other Applications of Newton’s Laws
Newton’s Laws of Motion
Presentation transcript:

Identical magnets are stuck at three radii on a rotating disc. The angular velocity of the disc is continually increased. What will happen to the magnets? 1.The magnets will remain attached to the disc. 2.The magnets will be thrown from the disc all at the same time. 3.The magnets will be thrown from the disc outermost first and innermost last. 4.The magnets will be thrown from the disc innermost first and outermost last. 5.Something else.

Non-Uniform Circular Motion Remember that if the velocity is not constant there is also a component of the acceleration parallel to the direction of the velocity. (Assuming the velocity only has a tangential component.) Radial force – changes direction. Tangential force – changes speed. Motion in Accelerated (Non-Inertial) Reference Frames Newton’s laws are only valid for inertial reference frames! In accelerated reference frames objects seem to accelerate in the presence of a force, where there is no force to cause this acceleration. This force is called a fictitious force, since it does not exist. A fictitious force has no action-reaction partner. Example: As car goes around a curve, the passenger slides towards the door on the outside of the curve. The person seems to be pushed towards the door due to a Centrifugal Force. The centrifugal force is a fictitious force. The car is accelerating, but the passenger is continuing to move in a straight line path that is tangential to the curve. The door exerts a force on the passenger to keep them inside the car.

Motion in the Presence of Resistive Forces. Resistive forces are forces that impede the motion of an object, with the most common being drag. Resistive forces usually depend on some characteristic of the motion, such as the speed of the object. One example of a resistive force is air drag, which is approximated by the expression shown below. This particular expression can only be used to approximate air drag for an object at high speeds. Notice that this resistive force depends on the square of the velocity and the cross-sectional area of the object. R – Resistive Force – Air Drag [N] D – Drag Coefficient [Dimensionless]  – Density of air [kg/m 3 ] A – Cross-Sectional Area [m 2 ] v – Speed of the object [m/s] Example: An object is dropped from rest at a very high altitude. As the object falls what happens? The speed of the object increases which increases the drag. The resistive force will eventually reach the weight of the object, how does the motion change when this occurs? The weight of the object will be equal to the drag. – No Acceleration. What can you say about the motion now? The object is now falling at a constant speed called Terminal speed. Depends on the shape of the object. D  0.5 for a sphere. Resistive forces can never cause an object to start moving in the opposite direction.

Example: A cubic box with sides 20 cm long and a mass of 20 kg is dropped from a high altitude. The density of air is 1.29 kg/m 3 and the box has a drag coefficient of (Assume gravitational acceleration is the near Earth value.) a)What is the acceleration of the box when the resistive force is equal to 60% of the weight of the box? b)What is the terminal speed of the box? c)What percentage of the weight would the resistive force have to be to cause an acceleration of 7.5 m/s 2 ? R W a) b) 0 c) The net acceleration of the box is in the negative y-direction. y

Mechanics Energy and Momentum

CH 5: Kinetic Energy, work and Power

What is energy? Energy is an abstract quantity used to describe our ability to do something. E.g.: Describes motion and changes to motion, the likelihood that chemical reactions take place, possibility of electron transitions to generate light, etc. We are more familiar with types of energy or noticing changes due to energy transfer What are some of the main classification we use for energy? Mechanical energy Electrical Energy Internal Energy Nuclear Energy What are some types of energy transfer? Heat Conduction Convection Radiation Methods of transferring energy. Flow of energy between two points We will only be discussing mechanical energy at this time. We will be using the concept of energy to develop new techniques for looking at dynamic systems and their interactions with their environment. We will begin by defining what we mean by system and environment. System – Small part of the universe we are examining. Single particle or object Collection of particles or objects Region of space Environment – Everything not in the system.