notes rb labs 3 and 4

Forces and Motion

Forces and Motion Lab 1 “Graphing Your Motion”; Pages 1-7 Lab 2 “Gravity’s Pull”; Pages 9 – 16 Lab 3 “Keep on Truckin’ ”; Pages 15 – 28 Lab 4 “Laws of Motion”; Pages 29 – 34 Lab 5 “ Work Made Easy”; Pages 41 – 56 Lab 6 “ Power to do Work”; Pages 57 – Lab 7 “ The Force of Friction”; Pages 35 - 40

Forces and Motion

Lab 3 “Keep on Truckin’ ”; Pages 17-28

Lab 4 “Laws of Motion”; Pages 29 – 34

Lab 3

Keep on Truckin’Keep on Truckin’

Key ObjectivesKey Objectives

The Student will:– Investigate and understand

concepts of speed, velocity and acceleration when describing motion.


The Student will:– Understand that velocity

measures the average speed of an object in a specific direction


The Student will:Take measurements to calculate the speed of a moving object

Key TermsKey Terms

SpeedVelocityAcceleration

SpeedSpeed

The change in position of an object per unit of time:– Miles per hour

MPH

– Meters per SecondM/Sec

VelocityVelocity

The measurement of the speed of an object in a specific direction

N, NE, E, SE, W , NW,, S, SW,

North Northeast East Southeast West Northwest South Southwest

AccelerationAcceleration

The increase in speed of an object per unit of time

Written in Meters per second per second

M/sec2

Essential LearningsEssential Learnings

Average speed is calculated by dividing distance by time

s = d/t

Speed = Distance

Time


Velocity describes both the speed and the direction of the motion of an object

It is reported in meters per second (m/sec) in a specific direction (m/sec N, E,W or S)


Acceleration is the change in velocity per unit of time– m/sec2 (meters per second per second)

An object moving with constant speed/velocity has no acceleration

Essential Learnings:Essential Learnings:

Acceleration is calculated by dividing the change in velocity by time

a = vf – vi

ta = accelerationvf = final velocity

vi = initial velocity t = time


On earth weight in Newtons is ~10 your mass in Kiligrams

On earth, acceleration due to the force of gravity is: 9.8 m/sec2 (meters per second per

second)


A decrease in velocity is negative acceleration– Deceleration


Objects moving in a circular motion are constantly accelerating because velocity and direction are constantly changing


A distance/time graph for acceleration is always a curve

One More Thing…

Constant Accelleration– http://www.youtube.com/watch?v=BGfPU_gyqm8

Acceleration Plus and minus– http://www.youtube.com/watch?v=ixF_Tf4pmE8

Lab 4

Newton’s 3 LawsNewton’s 3 Laws

Watch This…..

Newton’s Three Laws of Motion Newton’s Intro… Intro….

– http://www.youtube.com/watch?v=UVdqxYyFRKY


The student will:– Investigate and understand

the effects of gravity and Newton’s laws of motion


The student will:– Define Force and distinguish

between balanced and unbalanced forces


The student will:– Explain the effects of

balanced and unbalanced forces on the motion of an object


The student will:– Identify situations that illustrate

each law of motionGive examples of the effects of Inertia

(Newton’s First Law)


The student will:– Explain how force, mass and

acceleration are related

(Newton’s Second Law)


The student will:– Solve basic problems given

the formula; Force = mass x acceleration (F=ma)


The student will:– Demonstrate action and

reaction forces and how they apply to motion (Newton’s Third Law)


The student will:– Explain how force and motion

apply to car safety and technology, rockets and restraining devices

Key TermsKey Terms

Newton’s First Law– Inertia

Newton’s Second LawNewton’s Third LawBalanced ForcesUnbalanced Forces

Newton’s First LawNewton’s First Law

InertiaInertia– A body at rest will

remain at rest until a force acts upon it

and…


“A body will remain in motion and travel in a straight path and constant speed until a force acts upon it.”


InertiaInertia- Often called the “Lazy Law”…it says things do what they are doing until a force causes a

change to occur

Newton’s Second LawNewton’s Second Law

“The acceleration of an object depends on the mass of the object and the amount of force applied”

Newton’s Third LawNewton’s Third Law

“Whenever one object exerts a force on another, the second object exerts an equal and opposite force on the first”

Action Action Reaction or Reaction or

Cause Cause EffectEffect

Balanced ForcesBalanced Forces

When forces are equal or balanced no change in the motion of an object will be observed

Unbalanced ForcesUnbalanced Forces

When forces are unequal or unbalanced, a change in the motion of an object can be observed:– Bowling ball collides with a tennis

ball


Sir Isaac Newton (1642 – 1727) The “Father of Calculus” and one of the greatest Physicists ever

Through observations and calculations discovered three laws of motion.


Newton’s first law (Inertia) states:– Any object at rest will remain

at rest until a force acts upon it to change the objects position/motion.


– In addition, any moving object will remain in motion at a constant speed and in a straight line until another force acts upon it to change its motion.

.


Newton’s second law : – F=ma– The acceleration of an object is

determined by the mass of the object and the amount of force needed to change the speed


– Note that:Only an unbalanced force can change an objects motion


Newton’s third law :– For every action there is an equal

and opposite reaction.– Often called

Action ReactionCause and Effect

Newton’s Laws ReviewNewton’s Laws Review

http://www.youtube.com/watch?v=jFI29NoG-Ko

Newton’s Law SongNewton’s Law Song

http://www.youtube.com/watch?v=PkAO8F-Tm-w

Finally….Finally….

http://www.youtube.com/watch?NR=1&v=jwPc0kK9VHU&feature=fvwp

FormulaeFormulae

Force

F= maF = Force

m= Mass

a = acceleration

Formulae (Formulas)Formulae (Formulas)

Accelerationa=Vf – Vi

ta = acceleration t = time

Vf = Final Velocity

Vi = Initial Velocity

FormulaeFormulae

Distance

d= r x ts = speed

r = rate

d= Distance

Essential Learnings

The End!

notes rb labs 3 and 4

Technology