Post on 24-Dec-2015
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
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
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.
Unbalanced forces
Net force does not equal 0 Newton’s.Causes a change in direction or starts
movement.
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 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 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.
Which Law?
A magician pulls a tablecloth out from under dishes and glasses on a table without disturbing them.
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 rabbit’s legs exert a force on Earth. Earth exerts an equal force on the rabbit’s legs, causing the rabbit to accelerate upward.