Forces and Motion Investigate and apply Newton’s three laws of motion. Examine the law of conservation of momentum in real world situations Explore the difference between mass and weight Relate gravitational force to mass

Forces Push or pull that acts on an object Cause a resting object to move or cause acceleration Measured in Newtons, N The amount of force to accelerate a 1 kg object 1 m/s2 F=ma Arrows show the direction of force

Net Force Overall force acting on an object Balanced forces Equal and opposite force Net force is zero Unbalanced forces One opposing force is greater than another Forces going in the same direction Causes acceleration Net force greater than or less than zero

Friction Static Sliding Rolling Fluid Friction force on objects not moving Sliding Force in opposite direction of moving object Rolling Point at which round object slides against a surface Fluid Force in opposite direction of object in a fluid Air resistance-friction of object falling through air

Gravity Force between two objects that have mass Earth’s gravity always pulls objects to the center of Earth Objects accelerate down and fight air resistance Projectiles Follow a curved path because of gravity and air resistance An initial forward velocity and downward velocity

Newton’s Laws First Law Inertia Second Law Weight http://ia700202.us.archive.org/7/items/AP_Physics_C_Lesson_03/Container.html First Law Objects in motion stay in motion Objects in rest stay in rest Inertia Tendency of an object to resist change Second Law Force is equal to an object’s mass and acceleration F=ma Weight Force of gravity acting on an object Weight equals mass times gravity http://www.physicsclassroom.com/mmedia/newtlaws/cci.cfm

Newton’s Laws Continued http://ia600204.us.archive.org/13/items/AP_Physics_C_Lesson_05/Container.html Third Law For every action there is an equal and opposite reaction Action-reaction forces Force exerting on an object and force coming from an object to prevent movement

Momentum Greater mass, greater momentum Momentum equals mass times velocity Conservation of Momentum When two objects collide, momentum is transferred from one to the other http://ia600208.us.archive.org/10/items/AP_Physics_C_Lesson_13/Container.html

Universal Forces Electromagnetic Forces Nuclear Forces Can attract and repel Opposites attract, like charges repel Nuclear Forces Strong nuclear force holds protons and neutrons together in the nucleus Weak nuclear force is what causes radioactivity Gravitational Force Attraction between objects that have mass Mass and distance affect gravity Centripetal Force Center-directed force that allows an object to move in a circle