Forces.

Slides:



Advertisements
Similar presentations
The wind pushes against the man and his umbrella
Advertisements

Notes Titles: What is a Force? Combining Forces Friction Gravity
FORCES Mrs. Cholak.
Forces.
Chapter 2: Force and Newton’s Laws
Forces 1 Dynamics FORCEMAN. What causes things to move? Forces What is a force? –A push or a pull that one body exerts on another. 2.
Force and Newton’s Laws Newton’s First Law. A. Force—push or pull on an object 1. The combination of all the forces acting on an object is the net force.
SPS8.c Relate falling objects to gravitational force.
Types of Forces Gravity and Friction. Forces!!!!! PUSH Or A Pull.
Chapter 3 Forces.
Force and Its Representation
CHAPTER 3. Newton’s Second Law of Motion F = m × a Force = mass × acceleration The faster you run into a wall, the more force you exert on that wall Units.
Force A push or pull exerted on an object..
What is a Force? A force is a push or a pull causing a change in velocity or causing deformation.
Forces and Free Body Diagrams. Common Forces Gravity- attractive force between two objects that have mass. AKA Weight To calculate Weight: –Force of Gravity.
Chapter 12: Forces and Motion
Remember!!!! Force Vocabulary is due tomorrow
FORCE is any push or pull which causes something to move or change its speed or direction.
Motion & Forces.
Chapter 12 Forces and Motion.
Chapter 2 Physical Science
Forces Ch 7 6 th grade. 7.1 Vocabulary Force Net force.
Forces & Motion. What is a Force? Force: push or pull Unit: Newton (N)  Kg x m/s 2 Vector: has both magnitude & direction.
Forces. I. Section 1 A. Newton- (N) the SI unit for the magnitude of a force. Also called weight. B. Force- a push or a pull. Described by its magnitude.
Forces Motion and Forces. Forces What is a force? A force is a push or pull. What happens when forces combine? Forces combine to produce a net force.
Forces and Newton’s Laws of Motion. A force is a push or a pull. Arrows are used to represent forces. The length of the arrow is proportional to the magnitude.
Forces. Force is a push or a pull. is a push or a pull. a force is described by its strength and by the direction in which it acts. a force is described.
Forces Chapter 12, Section 1. Forces Force – a push or a pull that acts on an object Force – a push or a pull that acts on an object A force can cause.
FORCES CH. 2. What is a Force? Def: a push or a pull –Measured in Newtons Kg · m/s 2 –Balanced Force – an equal but opposite force acting on an object.
Forces 1 Dynamics FORCEMAN. What causes things to move? Forces What is a force? –A push or a pull that one body exerts on another. 2.
Forces and the laws of motion. Force A bat strikes the ball with a force that causes the ball to stop and then move in the opposite direction.
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.
Motion and Forces.
Newton’s First Law of Motion
The Laws of Motion Chapter 2.
Chapter 11: Force and Newton’s Laws
Forces change Motion.
Forces Chapter 3.
Chapter 8 Forces & Motion.
Chapter 13 Motion and Forces.
Lecture 8 Motion and Forces Ozgur Unal
Forces Ch
11.8 Forces Review.
Forces FORCEMAN.
Motion & Forces.
FORCE and MOTION Unit 1.
Ch 12Forces and Motion Support from ch 12/ Evidence
Forces.
Forces.
Forces.
SSA Review - 9 Forces & Motion
Do Now:.
Forces Affecting Motion
FCAT Review - 9 Forces & Motion
CHAPTER 4 FORCES IN 1-D.
Newton’s Laws of Motion Chapters 2,3,6,7
Forces.
Forces FORCEMAN.
Forces.
Chapter Menu Lesson 1: Combining Forces Lesson 2: Types of Force
Forces Unit 9 Lecture.
Forces and Motion Investigate and apply Newton’s three laws of motion.
Forces & Motion.
What Is a Force? A _______ is a push or a pull that acts on an object.
Force & Motion.
Force and Newton’s Laws of Motion
Gravitational Forces Physical Science.
Forces and Friction.
Newton’s 3rd Law and Free Body Diagrams
Lesson 3 Reading Guide - Vocab
Presentation transcript:

Forces

Newton’s 1st Law of Motion An object at rest will stay at rest, and an object in motion will stay in motion UNLESS acted on by an unbalanced force In other words: An object will keep doing what it’s doing until a force changes its motion

Forces A force is a push or a pull on an object All changing motion is caused by ONE or MORE forces. The SI unit for force is Newton (N).

Kinds of forces we will talk about Frictional Force Air Resistance Gravitational Force Tensional Force Applied Force Electrical Force Normal Force Spring Force Magnetic Force

Newton’s Second Law of Motion An object will accelerate in the same direction as the net force on an object! Force = mass x acceleration F = m x a

Net Force Net force = F1 + F2 + F3 + … The net force on an object is the sum of all the forces on the object in each direction. Net force = F1 + F2 + F3 + …

Practice Problem Bob the squirrel is mowing his lawn. A lawn mower is pushed across the ground with a force of 25 N. The ground provides 14 N of resistance. What is the net force on the lawn mower in the x-direction (along the ground)? Net Force = F1 + F2 + F3…… F1 = + 25 N F2 = - 14 N (negative because it is resisting) Net Force = (+25N) + (-14N) = 25N – 14N = 11N

TRY IT! If the mass of a helicopter is 4,500 kg. and the net force on it is 18,000 N, what is the helicopter’s acceleration? Given: Finding? m = 4,500 kg a = ? (acceleration) F = 18,000 N F = m x a a = F_ m = 18,000 N 4,500 kg a = 4 m/s2 F a m

Gravity Gravity is the attractive force between two objects Gravity’s strength depends on the masses of the objects and the distance between them

Force of Earth’s Gravity F = mg m is the mass of the object gravity is acting on g is the gravitational acceleration constant: g = 9.8m/s2 The “F” on Earth is weight.

Let’s try one! On earth, what is the weight of a television having a mass of 75 kg? F = mg where ‘F’ is weight m= 75 kg g = 9.8 m/s2 weight =? weight = (75 kg) (9.8 m/s2)= 735 kg x m/s2 weight = 735 N

Try one by yourself….. Find the acceleration due to gravity on Mars if a person with a mass of 60.0 kg weighs 22.2 N on Mars?

Normal Force Fnormal + Fgravity = 0 N When gravity acts on an object, but the object does not fall, there is a normal force pushing up on the object Fnormal + Fgravity = 0 N

Balanced Forces If an object is not accelerating, either: 1. no forces are acting on it, or 2. all the forces balance out Two forces are balanced if they have BOTH: equal sizes opposite directions

Unbalanced Forces Every force has a magnitude and a direction If the net force (sum of the magnitude in each direction) is not zero, the object accelerates Objects can have the same direction, but different magnitudes.

Force Diagrams Force diagrams use different sized arrows to represent the Forces acting on an object Including: sizes, directions, and type of force The object is usually represented by a box

EXAMPLE 1 Draw the forces affecting a textbook on the table BOOK BOOK

EXAMPLE 2 Draw the forces affecting a textbook being pushed across the table at a constant velocity BOOK BOOK

Example 3 Draw the force affecting a magnet being held to close to another magnet. N S S N S S N N S

Special Forces

Newton’s Third Law For every action force, there is an equal and opposite reaction force Action and Reaction forces do not cancel -they can act on different objects or spread in different directions

Air Resistance Air resistance is a force that opposes the motion of objects that move through air Air resistance depends on an object’s size, shape, and speed Ignore air resistance in this class unless you are told to include it

Friction Friction is the force that opposes motion. Sliding friction – opposes the motion of 2 surfaces as they slide against each other

Static Friction Static friction – prevents 2 surfaces from sliding against each other at all Rolling friction – slows down the motion of an object rolling on a surface Static friction keeps a wheel from spinning in place and makes it turn instead

Projectile Motion

The “nitty-gritty” of projectiles The only forces that acts on a projectile is gravity. So, the only acceleration is in the downward direction.

Types of Projectiles Drops- no initial velocity in the horizontal or vertical direction Throw vertically- initial velocity in the vertical, but not in the horizontal Launch- initial horizontal and vertical velocity