Post on 05-Dec-2014
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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.
Key ObjectivesKey Objectives
The Student will:– Understand that velocity
measures the average speed of an object in a specific direction
Key ObjectivesKey Objectives
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
Essential LearningsEssential Learnings
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)
Essential LearningsEssential Learnings
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
Essential LearningsEssential Learnings
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)
Essential LearningsEssential Learnings
A decrease in velocity is negative acceleration– Deceleration
Essential LearningsEssential Learnings
Objects moving in a circular motion are constantly accelerating because velocity and direction are constantly changing
Essential LearningsEssential Learnings
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
Key ObjectivesKey Objectives
The student will:– Investigate and understand
the effects of gravity and Newton’s laws of motion
Key ObjectivesKey Objectives
The student will:– Define Force and distinguish
between balanced and unbalanced forces
Key ObjectivesKey Objectives
The student will:– Explain the effects of
balanced and unbalanced forces on the motion of an object
Key ObjectivesKey Objectives
The student will:– Identify situations that illustrate
each law of motionGive examples of the effects of Inertia
(Newton’s First Law)
Key ObjectivesKey Objectives
The student will:– Explain how force, mass and
acceleration are related
(Newton’s Second Law)
Key ObjectivesKey Objectives
The student will:– Solve basic problems given
the formula; Force = mass x acceleration (F=ma)
Key ObjectivesKey Objectives
The student will:– Demonstrate action and
reaction forces and how they apply to motion (Newton’s Third Law)
Key ObjectivesKey Objectives
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…
Newton’s First LawNewton’s First Law
“A body will remain in motion and travel in a straight path and constant speed until a force acts upon it.”
Newton’s First LawNewton’s First Law
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
Essential LearningsEssential Learnings
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.
Essential LearningsEssential Learnings
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.
Essential LearningsEssential Learnings
– 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.
.
Essential LearningsEssential Learnings
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
Essential LearningsEssential Learnings
– Note that:Only an unbalanced force can change an objects motion
Essential LearningsEssential Learnings
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!