speed the distance traveled by an object divided by the time taken to travel that distance. speed =...
TRANSCRIPT
Force and Motion
Speed
The distance traveled by an object divided by the time taken to travel that distance.
Speed = distance/timeExample: Speed = 360km/4h = 90 km/h
Example for calculating speed:
What is the speed of the balloon that travels 20m in 10s?
Speed = 20m/10s = 2m/s
Velocity
The speed of an object in a particular direction.
Example: 30m/s north
Acceleration
The rate at which velocity changes.This can include a change in direction,
change in speed, or both.Acceleration = (final velocity – initial
velocity)/timeExample: (5m/s – 1m/s)/4s = 1m/s2 south
Forces
A push or pull.
Net Force: all the forces acting on an object.
Net Force
Forces acting in the same direction are added to determine net force.
Forces acting in different directions are subtracted to determine net force.
Balanced forces
Net force = 0 Newton'sWill not cause a change in motion.
Unbalanced forces
Net force does not equal 0 Newton’s.Causes a change in direction or starts
movement.
Determine the net force
What is the net force for situation A?
Net force = 0 N
Determine the net force
What is the net force for situation B?
Net force = 5N left
Determine the net force
What is the net force for situation C?
Net force =0 N
Determine the net force
What is the net force for situation D?
Net force =15N upward
Friction
Force that opposes motion between two surfaces that are in contact.
Example: Brakes of a car, tires and the ground.
Gravity
A force of attraction between objects that is due to their masses.
Large mass = strong gravity.Closer together = strong gravity.
Newton’s First Law of Motion
An object at rest remains at rest, and an object in motions remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.
Newton’s First Law of Motion
Also known as the law of inertia.Inertia is the tendency of an object to resist
any change in motion.Example: When you are in a car, your body is
moving. It wants to keep on moving.
Newton’s First Law of Motion
Video clip
Newton’s Second Law of Motion
The acceleration of an object depends on the mass of the object and the amount of force applied.
Ex. Empty cart vs. full cartEx. Small force vs. large force
Newton’s Second Law of Motion
Video Clip
Newton’s Third Law of Motion
Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.
Newton’s Third Law of Motion
All forces act in pairs.Action and reaction forces.Example: A rocket
Newton’s Third Law of Motion
Video Clip
Which Law?
A magician pulls a tablecloth out from under dishes and glasses on a table without disturbing them.
Which Law?
Pushing a child on a swing is easier than pushing an adult on the same swing.
Which Law?
Rockets are launched into space using jet propulsion where exhaust accelerates out from the rocket and the rocket accelerates in an opposite direction.
Which Law?
A soccer ball accelerates more than a bowling ball when thrown with the same force.
Which Law?
A person’s body is thrown outward as a car rounds a curve on a highway.
Which Law?
A rabbit’s legs exert a force on Earth. Earth exerts an equal force on the rabbit’s legs, causing the rabbit to accelerate upward.
It is…….
Newton’s First Law of Motion!
It is…….
Newton’s Second Law of Motion!
It is…….
Newton’s Third Law of Motion!
It is…..
Newton’s First Law of Motion!
It is……
Newton’s Second Law of Motion!
It is…….
Newton’s Third Law of Motion!
Great job!!!