Newton’s Laws and Newton’s Laws and MotionMotion

3 Laws of Motion3 Laws of Motion 11stst Law Law – An object at rest will stay at – An object at rest will stay at

rest, and an object in motion will stay rest, and an object in motion will stay in motion at constant velocity, unless in motion at constant velocity, unless acted upon by an unbalanced force.acted upon by an unbalanced force.

22ndnd Law Law – – Force equals mass times Force equals mass times acceleration.acceleration.

33rdrd Law Law – – For every action there is an For every action there is an equal and opposite reaction.equal and opposite reaction.

4 Types of Friction4 Types of Friction There are four main types of There are four main types of

friction:friction:– Sliding friction: Sliding friction: ice skating– Rolling friction: Rolling friction: bowling– Fluid friction (air or liquid): Fluid friction (air or liquid): air or

water resistance– Static friction: Static friction: initial friction when

moving an object

22ndnd Law Formula Law Formula How much force is needed to accelerate

a 1400 kilogram car 2 meters per second/per second?

1. Write the formula1. Write the formula F = m x a2. Fill in given numbers 2. Fill in given numbers F = 1400 x 2 3. Solve for the unknown3. Solve for the unknown2800 N

22ndnd Law Practice Law Practice 1. What acceleration will result when a 12 N net 1. What acceleration will result when a 12 N net

force is applied to a 3 kg object? A 6 kg object?force is applied to a 3 kg object? A 6 kg object?   2. A net force of 16 N causes a mass to 2. A net force of 16 N causes a mass to

accelerate at a rate of 5 m/saccelerate at a rate of 5 m/s22. Determine the . Determine the mass.mass.

3. How much force is needed to accelerate a 66 3. How much force is needed to accelerate a 66 kg skier 1 m/sec/sec?kg skier 1 m/sec/sec?

4. What is the force on a 1000 kg elevator that 4. What is the force on a 1000 kg elevator that is falling freely at 9.8 m/sec/sec?is falling freely at 9.8 m/sec/sec?

22ndnd Law Practice Law Practice AnswersAnswers 1. What acceleration will result when a 12 N net force applied to a 3 kg 1. What acceleration will result when a 12 N net force applied to a 3 kg

object? object? 12 N = 3 kg x 4 m/s/s12 N = 3 kg x 4 m/s/s

   2. A net force of 16 N causes a mass to accelerate at a rate of 5 m/s2. A net force of 16 N causes a mass to accelerate at a rate of 5 m/s22. .

Determine the mass.Determine the mass. 16 N = 3.2 kg x 5 m/s/s16 N = 3.2 kg x 5 m/s/s

   3. How much force is needed to accelerate a 66 kg skier 1 m/sec/sec?3. How much force is needed to accelerate a 66 kg skier 1 m/sec/sec?

66 kg-m/sec/sec or 66 N66 kg-m/sec/sec or 66 N

4. What is the force on a 1000 kg elevator that is falling freely at 9.8 4. What is the force on a 1000 kg elevator that is falling freely at 9.8 m/sec/sec?m/sec/sec?

 9800 kg-m/sec/sec or 9800 N9800 kg-m/sec/sec or 9800 N

ALL NOTES TO THIS POINT ARE ALL NOTES TO THIS POINT ARE FOR THE QUIZFOR THE QUIZ

PRINT REMAINING NOTES AS PRINT REMAINING NOTES AS SLIDES AS A HANDOUT TO TEACH SLIDES AS A HANDOUT TO TEACH FOR THE TESTFOR THE TEST

Air resistance- Air resistance- fluid friction acting fluid friction acting on an object moving through airon an object moving through air

Acceleration-Acceleration- rate at which an rate at which an object’s velocity changesobject’s velocity changes

Gravity- Gravity- force that exists between force that exists between any two objects that have mass, any two objects that have mass, attracting or pulling them togetherattracting or pulling them together

Friction-Friction- force that opposes motion, force that opposes motion, or resistance, caused when two or resistance, caused when two surfaces touch or rub togethersurfaces touch or rub together

Speed-Speed- rate at which the position of rate at which the position of an object changesan object changes

Inertia-Inertia- tendency of a still or moving tendency of a still or moving object to resist a change in its motionobject to resist a change in its motion

Kinetic energy-Kinetic energy- energy an object has energy an object has due to its motiondue to its motion

Velocity-Velocity- rate at which an object rate at which an object moves in a certain directionmoves in a certain direction

Mass-Mass- amount of matter in an object amount of matter in an object Force-Force- push or pull that acts on an push or pull that acts on an

object, causing it to move, change object, causing it to move, change speed or direction, or to stop movingspeed or direction, or to stop moving

Momentum-Momentum- property of matter due property of matter due to its mass and velocityto its mass and velocity

Weight-Weight- measure of the force of measure of the force of gravity acting on an objectgravity acting on an object

Potential energy-Potential energy- energy that is energy that is stored, available as a result of an stored, available as a result of an object’s position or conditionobject’s position or condition

Newton-Newton- unit of force unit of force

Motion-Motion- the process of changing the process of changing from one from one positionposition, or place, to , or place, to another. another.

Displacement-Displacement- describes both describes both how far an object moved from its how far an object moved from its original position and in what original position and in what direction direction it moved. it moved.

Example of displacement: Example of displacement: A runner follows a path through a park A runner follows a path through a park

and goes 3 kilometers north, turns and goes 3 kilometers north, turns right, and travels 4 kilometers east. right, and travels 4 kilometers east. The total distance traveled is 7 The total distance traveled is 7 kilometers, but her final position is kilometers, but her final position is only 5 kilometers northeast of her only 5 kilometers northeast of her starting point. So her displacement is starting point. So her displacement is 5 kilometers northeast. 5 kilometers northeast.

Law of conservation of Law of conservation of momentum:momentum:– momentum= mass x velocitymomentum= mass x velocity– Momentum of an object does not Momentum of an object does not

change unless its mass changes, its change unless its mass changes, its velocity changes, or both changevelocity changes, or both change

– If there is no outside force acting, If there is no outside force acting, momentum will not changemomentum will not change

Free fall-Free fall- when gravity alone is when gravity alone is acting on an objectacting on an object– Astronauts experience this in their Astronauts experience this in their

aircraftaircraft

Finding speedFinding speed– Speed = distance / timeSpeed = distance / time– Example: A cruise ship travels 1,000 Example: A cruise ship travels 1,000

km in 25 hours. Their average speed km in 25 hours. Their average speed is 1000/25= 40 km per houris 1000/25= 40 km per hour

Net force- the force that results from all the combined forces acting on an object

Balanced force- forces that completely cancel each other out

Example- You are holding a piece of pizza. The force of gravity pulling it down is equal to the amount of force your hand is providing to hold it up.

Unbalanced force-when forces act on each other and do not cancel out

Example- The game of tug of war. When one team pulls harder, the force is unbalanced and the opposing team starts to move.

Displacement example A robot went 20 feet south, 20

feet west, and 20 feet north.

Average Speed Example Mr. Robot travels 500 feet in 2

minutes. What is his average speed?