Download Week 17 - Crossroads Academy

6th Grade Science
Dr. Whipple
Week 17
Jan 2nd – 6th, 2017
Welcome back everybody! I hope you had a fun and restful break!!
In class this week we will:
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Review our notebook assessment on astronomy.
begin to investigate how to measure speed, direction, velocity and
acceleration of any mass – as described by Newton’s three laws of
motion
watch a documentary on the greatest scientist of physics Sir Isaac
Newton
Some new terminology we will begin using:
• speed
• velocity, constant velocity
• vector quantity
• scalar
• inertia
• net force
• support force
• applied force
• mechanical equilibrium
• static vs. dynamic equilibrium
Some general concepts we will be covering:
• Scalar… a scalar quantity has only magnitude (number or amount).
Examples of scalar quantities are: time, the mass of an object, the volume
of an object, and density.
• Vector… a vector quantity has both magnitude (number) and direction.
Examples of vector quantities that we will discuss in class are:
displacement (how far and in what direction), velocity (the speed plus the
direction), and acceleration (gravity acts at 9.8 m/s2 downward).
• Newton’s first law of motion is the Law of Inertia…A body at rest remains at
rest and a body in motion remains in motion unless acted upon by an
outside force.
• The second law is Force = Mass x Acceleration.
• Force…force is a push or a pull…measured in a unit called a Newton. A
Newton is the force needed to accelerate a 1 kilogram object at 1 meter per
second, during each second the object travels.
• Acceleration is a change in speed or direction.
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Velocity has both speed and direction and is a vector quantity.
Speed is a “scalar”…like temperature, it has NO direction.
A car traveling in a circle at constant speed is accelerating.
A car slowing down is accelerating.
Friction opposes motion…slows moving objects.
Net force – combination of all forces acting on an object – its what changes
an objects state of motion
Some practical applications of the concepts: (try to answer these on your
own by Monday, Jan. 9th)
1) A ball rolling on a pool table slowly comes to a stop. How would Aristotle
explain this behavior? How would Galileo explain it?
2) What is the average speed of a cheetah that sprints 100 m in 4 s? How
about if it sprints 50 m in 2s?
3) The speedometer on a bicycle moving east reads 50 km/hr. It passes
another bicycle moving west at 50 km/hr. Do both bikes have the same
speed? Do they have the same velocity?
4) If a gymnast hangs with her weight evenly divided between the two rings,
how would scale readings in both supporting ropes compare with her
weight? What if she hangs with slightly more of her weight supported on
the left ring? How would the scale on the right read?
Homework:
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By Thursday, Jan. 5th, visit the following link
http://www.physicsclassroom.com/class/1DKin/Lesson-1/Introduction
and read through the sections:
Introduction
Scalars and Vectors
Distance and Displacement
Speed and Velocity
Acceleration
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Recopy your notes each night on the day that you take them!