Motion & Forces Amusement Park Forces

What is a Force? FORCE = Any push or pull which causes something to move or change its speed or direction

Balanced Force 30N 30N The net force on an object is zero and the object’s motion does not change. Image: http://image.wistatutor.com/content/force-laws-motion/balanced-force-example.jpeg; Definition: www.thefreedictionary.com

Unbalanced Force 50N 20N The net force of an object does not equal zero which results in a change in the motion of the object. Image: http://image.wistatutor.com/content/force-laws-motion/unbalanced-force-example.jpeg; Definition: www.thefreedictionary.com

What is a Force? Forces can be BALANCED or UNBALANCED Balanced forces are equal in size and opposite in direction unbalanced forces are not equal in size and/or opposite in direction. If the forces on an object are UNBALANCED, we say a NET force results. Amusement Park Forces

What is a Force? Balanced Forces? Unbalanced Forces? Can you think of examples of forces? Balanced Forces? Unbalanced Forces?

Net Force The sum of all the forces acting on an object. (same direction=add, opposite directions= subtract) Image: http://zonalandeducation.com/mstm/physics/mechanics/forces/netForce/netf3.gif; Definition: www.thefreedictionary.com

What is Motion? Motion: A change in position of an object compared to a reference point Motion involves all of the following:

Forces affect Motion: They can make objects start moving. They can make objects move faster. They can make objects move slower. They can make objects stop moving. They can make objects change direction. They can make objects change shape.

Gravity is a Force GRAVITY: An attraction force between all masses Newton’s universal law of gravitation: Every object in the universe exerts a gravitational attraction to all other objects in the universe The amount of gravitational force depends upon the mass of the objects and the distance between the objects

What is Friction? What are some ways athletes uses friction?

Friction is a Resistance Force Friction = A force that opposes or slows down motion Caused by the physical contact between moving surfaces The amount of friction depends upon the kinds of surfaces and the force pressing the surfaces together Changes motion into heat

The rate of change in position What is Motion? Speed The rate of change in position Speed = distance ÷ time or = distance time

Velocity What is Motion? Speed plus direction Example: 50 km/hour north

Acceleration What is Motion? The rate of change in velocity Positive acceleration = speeding up Negative acceleration = slowing down (decelerate) A change in the speed rate and/or direction, (velocity), of an object over time.

Acceleration by Brainpop ) What units are used to measure speed? ) What units are used to measure acceleration? ) What is another way to say “slowing down” in terms of acceleration? What units are used to measure velocity?

Newton's Laws of Motion

Newton's Laws of Motion First Law(Law of Inertia): An object at rest stays at rest or an object in motion, stays in motion (in the same direction/at the same speed) unless acted upon by an unbalanced force

The tendency of an object to resist any change in its motion Inertia The tendency of an object to resist any change in its motion The greater the mass the greater the inertia The greater the speed the greater the inertia

Examples of Newton’s 1st Law (do not copy) a) car suddenly stops and you strain against the seat belt b) when riding a horse, the horse suddenly stops and you fly over its head c) the magician pulls the tablecloth out from under a table full of dishes d) the difficulty of pushing a dead car e) lawn bowling on a cut and rolled lawn verses an uncut lawn f) car turns left and you appear to slide to the right

Examples of Newton’s 1st Law of IInertia

Newton's Laws of Motion Second law (Law of Force and Acceleration): The greater the force, the greater the acceleration The greater the mass, the greater the force needed for the same acceleration Calculated by: F = ma (F = force, m = mass, a = acceleration)

Examples of Newton’s 2nd Law of Force and Acceleration (do not copy) a) hitting a baseball, the harder the hit, the faster the ball goes b) accelerating or decelerating a car c) The positioning of football players - massive players on the line with lighter (faster to accelerate) players in the backfield d) a loaded versus an unloaded truck

Examples of Newton’s 2nd Law

Newton's Laws of Motion Third law (Law of Action-Reaction): For every action force, there is an equal and opposite reaction force. (Forces are always paired)

Examples of Newton’s 3rd Law (Do not copy) rockets leaving earth guns being fired c) two cars hit head on d) jumping out of a boat onto the dock

Examples of Newton’s 3rd Law