What is motion?

Acceleration

Momentum

Changing Position◦All matter in universe is constantly in motion◦If something is changing position it is in

motion◦To determine if an object is in motion, a

point of reference is needed

Final position of motion depends on both distance traveled and the direction

Distance would be the actual movement from start to end

Displacement includes the distance between start and finish and the ending point…. Sometimes it will be equal to zero, if you end up at same point that you started

See example on page 523

Speed is the distance an object travels in a period of time

S = D/T (units would be meters/second)

Average speed is found by taking total distance traveled by the total time

Instantaneous speed is the speed of an object at one instant of time (police using radar is an example)

Constant speed is speed that doesn’t vary on its movement (cruise control on car is put on constant speed)

Graphing using time (x axis) and distance (y axis) Constant speed

Which I moving at a faster pace?

Velocity of an object is the speed of an object and the direction of its motion

The difference of velocity and speed is that velocity refers to a direction

Velocity changes if you change speed or if you change direction

V = D/T (any changes in speed or direction changes its velocity)

Units are in m/s

Speeding up: a positive acceleration results in an object speeding up

Slowing down: a negative acceleration results in an object slowing down also known as deceleration

Changing Direction: Any change of direction results in change of velocity and a change in acceleration

Page 531

To solve physic problems these steps need to be shown on your paper◦ 1. list all information given◦ 2. write down what your ask to solve◦ 3. write down formula that you are using◦ 4. plug in data into formula including units◦ 5. solve and check if the answer makes sense◦ 6. record answer with its proper units

Bike increases speed from 4 m/s to 6 m/s in 5 seconds

Vi = 4 m/s A= 6m/s – 4 m/s Vf = 6 m/s 5 s T = 5 s A = ? A = .4 m/s/s or .4 m/s2

A= Vf-V bike speeds up .4 m/s every second T

Bike slows down from 4 m/s to 2 m/s in 5 seconds

Vf = 2 m/s A = 2 m/s- 4m/s Vi = 4 m/s 5s T = 5 s A=?

◦ A = -.4 m/s/s or -.4 m/s2

A = Vf-Vi (notice it is a negative acceleration)

T

Graphing accelerated Motion

http://www.physicsclassroom.com/mmedia/index.cfm#kinema

When a collision occurs changes in motion of the colliding objects depends on their masses and their velocities before the collisions

Mass: is the amount of matter in an object (the more mass, the harder to change its motion)

The tendency of an object to resist a change in its motion is called inertia and is dependent on its mass

A larger mass or an object moving faster is harder to stop than a smaller one or a slower one

Momentum is a measure of how hard it is to stop an object and is dependent on the objects mass and velocity

P = mv (where P is momentum, m is mass and v is

velocitiy)

Use the same process as before

To solve physic problems these steps need to be shown on your paper

1. list all information given2. write down what your ask to solve3. write down formula that you are using4. plug in data into formula including units5. solve and check if the answer makes sense6. record answer with its proper units

Calculate momentum of a 14 kg bike traveling 2m/s

M=14 kg p = mv V= 2m/s P =? P = 14 kg X 2 m/s p = 28 kg*m/s

The total momentum of a group of objects remains constant unless outside forces act on the group is known as the law of conservation of momentum

In a cue ball hitting billiard balls all the momentum of the original collision equals all of the momentums of the billiard balls when they are hit excluding outside force like friction

Some collisions bounce off each other, others stick together after contact

Momentum before equals momentum after collisions

p =p M1V1 =M2V2

Page 536 backpack weighs 2 kg is thrown at velocity of 5 m/s east. A student grabs it that weighs 48 kg. What was his velocity after catching it

Mbp = 2 kg Mbp(Vbp) = (Ms + Mbp)(Vs) Vbp = 5 m/s 2kg*5m/s=(2 kg+48kg)*Vs

Ms = 48 kg 10kg*m/s=50kg*V2

Vs = ? .2 m/s east = Vs

2 objects same mass and same speed collide Since they have same momentum before collision, they

have zero momentum

After collision the 2 objects bounce off with same velocity but opposite directions, therefore there is no momentum after collision