MOTIONStandards:

S8P3 – Investigate the relationship between force, mass, and the motion of objects.

S8P3a – Demonstrate the effect of balanced and unbalanced forces on objects in terms of gravity, inertia, and friction.

Essential Questions:How can you describe an object’s motion?

What causes an object’s motion to change?

Motion• An object is in motion if its distance from

another object is changing.

Reference Point• A place or object used for comparison to

determine if something is in motion.

Measuring Distance• Scientists use the

INTERNATIONAL SYSTEM OF UNITS (SI UNITS) to communicate their measurements clearly.

Speed• The speed of an object is the distance the

object travels per unit of time.• Speed = Distance

Time

Average Speed• The total distance traveled divided by the total

time.• Average Speed = Total Distance

Total Time

Instantaneous Speed• The rate at which an object is moving

at a given instant in time.

Velocity• Speed in a given direction.

Slope• The steepness of a line on a graph.

• Slope = Rise Run

Assignment:•Make sure you have

completed workbook pages 128-129 #’s 1-9•Complete workbook page

130-132 #’s 1-8

Wait for me to give you your assigned seat.•Once you are seated, open

your textbook to p.320 and open your composition book. Have a pencil/pen ready.

Acceleration• The rate at which velocity changes.• Refers to increasing speed,

decreasing speed, or changing direction.

Warm-Up:• In your composition book,

solve the following: If a snowflake is falling at 1m/s, and 4 seconds later, it is falling at 5m/s, what is its rate of acceleration?

Force• A force is a push or a pull, described

by its strength and the direction in which it acts, measured in SI unit called the NEWTON.

Net Force• The combination of all forces acting

on an object; it determines whether an object moves and also in which direction it moves.

Unbalanced Forces• Cause an object to start moving, stop

moving, or change direction.• Result in a net force and cause a

change in the object’s motion.

Balanced Forces• Equal forces acting on one object in

opposite directions.• Do not change the object’s motion.

Assignment:• complete workbook pages

137-138 #’s 1-12

Warm-UP• If I were to drop a golf ball and a

ping-pong (table tennis) ball from the same height at the same time, which would reach the ground first? Explain your answer.

Friction• The force that two

surfaces exert on each other.• Strength depends on

how hard the surfaces push together and the types of surfaces involved.

Static Friction• The friction that

acts on objects that are not moving.• Ex: your desk sitting

on the floor.

Sliding Friction• The friction that

occurs when two solid surfaces slide over each other.• Ex: sticky ballet

shoe powder to prevent slipping

Rolling Friction• The friction that

occurs when an object rolls across a surface.• Ex: wheels on

skateboards

Fluid Friction• The friction that

occurs when a solid object moves through a fluid.• Ex: cyclists’

streamlined helmets

Gravity• A force that pulls

objects toward each other.• The LAW OF

UNIVERSAL GRAVITATION states that the force of gravity acts between all objects in the universe.

Factors Affecting Gravity• MASS – a measure of

the amount of matter in an object (kg).• DISTANCE BETWEEN

OBJECTS – the farther apart two objects are, the lesser the gravitational force between them.

Weight and Mass• MASS – a measure of

the amount of matter in an object (kg).• WEIGHT– The force

of gravity on a person or object at the surface of a planet..

Free Fall• When the only force

acting on an object is gravity, it is in free fall. • The force of gravity is

unbalanced, which causes an object to accelerate.• Acceleration is 9.8m/s2

Air Resistance• A type of fluid friction objects falling

through air experience.

Terminal Velocity• The greatest

velocity a falling object reaches when the force of air resistance equals the weight of the object.

Projectile Motion• An object that is

thrown is a projectile.• A projectile will

fall at the same rate as any dropped object.

Warm-up:•Recall Newton’s 1st and 2nd Laws… try to put them in your own words!

Newton’s First Law (Inertia)•An object at rest will remain at rest, and an object moving at a constant velocity will continue moving at a constant velocity, unless it is acted upon by an unbalanced force.

Inertia depends on mass. •The more mass an object has, the harder it is to change the rate of acceleration.

Newton’s Second Law•Acceleration depends on the object’s mass and on the net force acting on the object.•Acceleration = net force mass

Newton’s Third Law•If one object exerts a force on a second object, the second object exerts a force of equal strength in the opposite direction on the first object.

Momentum•A characteristic of a moving object that is related to the mass and velocity of the object.•Momentum = Mass x Velocity

Law of Conservation of Momentum

•The total momentum of any group of objects remains the same, or is conserved, unless outside forces act on the objects.

Centripetal force•Any force that causes an object to move in a circular path.

Amusement Park Fun

Pressure• A force exerted

over an area on the surface of an object.

• Pressure decreases as the area over which a force is distributed increases.• It is measured in

Newtons/square meter (N/m2) …aka the PASCAL• Write this ------------

Fluid Pressure• All of the forces

exerted by the individual particles in a fluid combine to make up the pressure exerted by the fluid.• Air pressure is an

example of fluid pressure.

Balanced Pressure• In a stationary

fluid, pressure at a given point is exerted equally in all directions.

Atmospheric Pressure• As your

elevation increases, atmospheric pressure decreases; there’s less air above you!

Water Pressure• Water pressure increases as depth

increases; there’s more air PLUS water above you!

Barometer• An

instrument used to measure atmospheric pressure.

Buoyancy• The ability to float.• The buoyant force

acts in the direction opposite to the force of gravity, so it makes an object feel lighter.

Archimedes’ Principle

• The buoyant force acting on a submerged object is equal to the weight of the fluid the object displaces.

Pascal’s Principle• When force is applied to a confined fluid, the

change in pressure is transmitted equally to all parts of the fluid.

A HYDRAULIC SYSTEM multiplies force by applying the force to a small surface area; the increase in pressure is then transmitted to another part of the confined fluid, which pushes on a larger surface area.

Bernoulli’s Principle• As the speed

of a moving fluid increases, the pressure within the fluid decreases.

LIFT = an upward force