A. Motion is when an object changes its position relative to a reference point ( an object or place is used to determine if an object changes position).

Displacement vs. distance 1. Distance – how far something moves 2. Displacement – the distance and direction of an object’s change in position from its starting point

d s t B. Speed is the distance an object travels per unit of time 1. The rate is any change over time. 2. To calculate speed take the distance traveled and divide it by the time it took to travel that distance. Example: If I drove 100 km in 2 hours I would take 100 and divide it by 2. Answer would be 50 km per hour. 100  2  50

Equation  V = d ÷ t  v (speed), d (distance), t (time)  Variations:  to find d (distance) you use vt  to find t (time) you use d ÷ v Pyramid d v t Divide line Multiply line

3. Constant speed is the same speed throughout the trip. 4. Average speed is not the same throughout the trip; add the total distance and divide by the total time. Speed = total Distance / total Time

5. Instantaneous speed is speed at any given moment.

Graphing speed

D. Velocity is Speed in a given direction Velocity can change even if speed is constant as long as direction changes

II. Acceleration A. The rate of change of velocity 1. +a = speeding up; 2. -a = slowing down 3. A change in speed or direction is called acceleration.

B. Calculating acceleration 1. a = (v f – v i ) / t or a =  v / t 2. (v f – v i ) 3. Units are m/s/s

Example: constant speed & acceleration

Graphing Acceleration

D. Forces 1. A force is a pull or push.

Balanced and Unbalanced Forces  When an object moves at a constant speed or is stationary, the forces are balanced.  Balanced forces will not change an object’s motion.  When an object moves at a constant speed or is stationary, the forces are balanced.  Balanced forces will not change an object’s motion.

Balanced and Unbalanced Forces There generally is no motion when you lean against a wall. The force you exert by leaning is less than the capacity of the wall to support you or push back. This type of force is called a balanced force What if you could push against the wall with more force than it was able to withstand? The wall would likely fall over or you would push your hands through it. This is an example of an unbalanced force or a net force.

Unbalanced forces

Law of Inertia  1 st Law – An object at rest will stay at rest, and an object in motion will stay in motion at constant velocity, unless acted upon by an unbalanced force.  Unbalanced forces acting on an object will cause it to start moving, stop moving or change direction.  1 st Law – An object at rest will stay at rest, and an object in motion will stay in motion at constant velocity, unless acted upon by an unbalanced force.  Unbalanced forces acting on an object will cause it to start moving, stop moving or change direction.

Inertia an object’s resistance to a change of motion.  All matter has mass.  Inertia is dependent on the amount of mass an object has.  All matter has mass.  Inertia is dependent on the amount of mass an object has. The greater the mass of an object the greater the object’s inertia. The more difficult to start or stop an object.

Inertia  If the car is stopped suddenly the passenger will continue moving forward.  The passenger has inertia and that’s why we wear seat belts.  If the car is stopped suddenly the passenger will continue moving forward.  The passenger has inertia and that’s why we wear seat belts.

Inertia Why didn’t the penny move with the index card? The penny’s inertia(doesn’t move unless acted on by an unbalanced force.) What happens when you slowly flick the card?

2 nd Law Acceleration= Force equals mass multiplied by acceleration  F = ma  Force is any push or pull that can affect motion  Mass in kg, acceleration in m/s 2  Newtons: 1N = 1kgm/s 2 And can be rewritten as:  Acceleration equals Force divided by mass. Acceleration= Force equals mass multiplied by acceleration  F = ma  Force is any push or pull that can affect motion  Mass in kg, acceleration in m/s 2  Newtons: 1N = 1kgm/s 2 And can be rewritten as:  Acceleration equals Force divided by mass.

Newton’s 2nd law  What is the force applied by a mass of 2 kg with an acceleration of 6 m/s 2 ? 1.6 N 2.3 kg ● m/s 3.12 kg ● m/s 2  What is the force applied by a mass of 2 kg with an acceleration of 6 m/s 2 ? 1.6 N 2.3 kg ● m/s 3.12 kg ● m/s 2

 What is the acceleration of a mass of 6 kg applying a force of 24 N? 1.4 m/s m/s m/s 2  What is the acceleration of a mass of 6 kg applying a force of 24 N? 1.4 m/s m/s m/s 2

 Since both vans have the same engine, both have an applied force on them that is equal.  The truck with the large inertia will have a small acceleration, while the truck with less inertia will have greater acceleration.  inertia is what resists a change in velocity.  The more inertia (more mass), the less the change in velocity there will be. The greater the mass, the smaller the acceleration.  Since both vans have the same engine, both have an applied force on them that is equal.  The truck with the large inertia will have a small acceleration, while the truck with less inertia will have greater acceleration.  inertia is what resists a change in velocity.  The more inertia (more mass), the less the change in velocity there will be. The greater the mass, the smaller the acceleration.

 Surfaces can appear smooth, but microscopically you can observe peaks and valleys which cause the friction.

Microscopic look at a smooth surface

acts in a direction opposite to the direction of an object’s motion.

Friction is a force that affects motion.  There are four main types of friction:  Sliding friction: ice skating  Rolling friction: bowling  Fluid friction (air or liquid): air or water resistance  Static friction: initial friction when moving an object  There are four main types of friction:  Sliding friction: ice skating  Rolling friction: bowling  Fluid friction (air or liquid): air or water resistance  Static friction: initial friction when moving an object

Gravity pulls objects toward one another Weight is equal to the force of gravity on an object on the surface of a planet.

Newton’s Third Law  For every action, there is always an opposite and equal reaction. . The reaction, or motion, of the rocket away from the launch pad is equal to and opposite from the thrust of the engine or nozzle.  For every action, there is always an opposite and equal reaction. . The reaction, or motion, of the rocket away from the launch pad is equal to and opposite from the thrust of the engine or nozzle.

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