Forces & Motion

Big Ideas Every force is part of an interaction between two objects Forces are pushes and pulls that can be contact or non-contact forces Motion is described relative to something else (point of reference) A change in motion is due to unbalanced forces No change in motion and an object at rest are due to balanced forces

Forces Force: a push or pull that causes an object to accelerate in the direction of the force Contact Forces: pushes and pulls that result from direct touching of objects Friction: the force of two surfaces in contact with each other Non-contact Forces: pushes and pulls that result without the direct touching of objects acting at a distance

Magnetic attraction: a force that pulls objects with opposite poles towards on another Magnetic repulsion: a force that pushed objects with the same poles away from one another Gravitational force: a force that pulls objects toward each other. This force acts between all objects.

Identify the following as Contact or Non-Contact Forces A foot kicking a soccer ball An apple falling off a tree A paper clip sliding towards a magnet A bat stricking a baseball Two magnets pushing apart from one another The moon orbiting the Earth A compass needle turning North A hand pushing an object Shoes rubbing against the floor

Contact Forces Friction Drag (air resistance) Physical Contact with an object Non-Contact Forces Gravity Magnetism

Magnetism http://player.discoveryeducation.com/index.cfm?guidAssetId=FF1B9001-1689-4319-B062-F13E2EB2F7C6&blnFromSearch=1&productcode=US

Create a Cartoon Today you are making a cartoon strip. Your cartoon strip should be about a super hero who uses the power of forces to save people. Your cartoon should have eight sections that include examples of: 3 Contact Forces 3 Non-Contact Forces Labels for each force Color

Balanced & Unbalanced Forces http://player.discoveryeducation.com/index.cfm?guidAssetId=04269900-C995-41A9-8DFC-B16580A3CCE8&blnFromSearch=1&productcode=US

Net force: the combination of all forces acting on an object Net force: the combination of all forces acting on an object. This determines if an object moves and in which direction Non-zero net force: when forces act in the same direction the net force is found by adding the strengths of the individual forces. When forces act in opposite directions, they combine by subtraction. Zero net force: when the combined forces are zero. The motion of an object will not change. (If it is at rest it stays at rest, if it is in motion it stays in motion) Balanced force: equal forces acting on one object in opposite directions. These do not change the object’s motion Unbalanced forces: whenever a net force acts on an object. This can cause it to start moving, stop moving or change direction

Unbalanced Forces http://www.mansfieldct.org/schools/mms/staff/hand/lawsunbalancedforce.htm