1/29 Warm Up In your own words, what do you think “physics” is? List 5 things you expect to learn in the “physics” part of our course. 1) 2) 3) 4) 5)

Quiz Monday and Tuesday 1/29 Agenda Do Now Section 11.1 and 11.2 Notes Worksheet HW: none Quiz Monday and Tuesday

Finish Section 11.1 and 11.2 Notes Worksheet HW: Pgs 1,2 1/27 Agenda Do Now Finish Section 11.1 and 11.2 Notes Worksheet HW: Pgs 1,2 Quiz Monday and Tuesday

Chapter 11 Motion

11.1 Distance and Direction Choosing a frame of reference To describe motion accurately and completely, a frame of reference is necessary. Ex: A butterfly moves, but so does the Earth. Frame of reference-system of objects that are not moving with respect to one another. How fast are you moving? Relative Motion- Movement in relation to a frame of reference. Ex: A train to people on a platform is moving. To people on the train, they don’t seem to be moving.

Measuring Distance Distance- The length of a path between two points. Measuring Displacement Displacement is the direction from the starting point and the length of a straight line from the starting point to the ending point. Directions use displacements Ex: Walk 5 blocks north. Do Quick Lab on comparing distance and displacement Walk around desks… tape measurer.

Combining Displacement Vector- A quantity that has a magnitude and a direction. Magnitude can be size, length, or amount. Vector addition is the combining of vector magnitudes and directions. You can add displacements using vector addition. Displacement among a straight line

Vector addition “Tip to tail”

When displacement isn’t a straight path… Use Resultant vector- The vector sum of 2 or more vectors. It shows displacement. Measuring the resultant vector (the diagonal red line) shows that the displacement from the boy's home to his school is two blocks less than the distance he actually traveled

11.2 Speed and Velocity Speed- the ratio of the distance an object moves to the amount of time the object moves. SI unit of speed is (m/s) meters per second

What’s the difference? Distance vs Displacement? Speed vs Velocity? ___________________________________ Distance vs Displacement? Has no direction Has a direction Ex: 5m 5 m up Speed vs Velocity? Ex: 35 km/hr 35 km/hr west

Ways to express speed Instantaneous speed- measured at a particular instant. Instantaneous Speed, v, the rate at which an object is moving at a given moment in time. Example: A car’s speedometer.

Ways to express speed Average speed- computed for the entire duration of a trip. speed-, v, is the total distance traveled, d, divided by the time, t, it takes to travel that distance. Average speed = Total distance or v = d total time t

Math practice 1.A person jogs 4.0 kilometers in 32 minutes, then 2.0 kilometers in 22 minutes, and finally 1.0 kilometer in 16 minutes. What is the jogger's average speed in kilometers per minute? 2.A train travels 190 kilometers in 3.0 hours, and then 120 kilometers in 2.0 hours. What is its average speed?

1/30 Do Now (on your notes packet) What is the velocity of a car that traveled a total of 75 Km North in 1.5 hrs? What is the velocity of a plane that traveled 3000 miles from NY to CA in 5 hours?

Do Now Go over HW Quiz Graphing Practice pg 7,8 HW:3,4,7,8,10,11,16,17 1/30 Agenda Do Now Go over HW Quiz Graphing Practice pg 7,8 HW:3,4,7,8,10,11,16,17 Quiz Wednesday - Math

Graphing Motion: Distance-Time Graphs The slope = change in distance change in time The slope of a line on a distance-time graph is speed. Velocity- speed and direction on which an object is moving. Velocity is a vector. If speed remains constant, a change in direction is a change in velocity.

2/1 Do Now (write in your notes) Think back to your past week walking, or in a car, or elsewhere…. When have you sped up? What have you slowed down?

Quiz Monday - Accleration 2/1 Agenda Do Now Go over HW Quiz Finish Graphs Acceleration Notes HW: 5,6,14,15 (due Fri) Quiz Monday - Accleration

Combining velocities Two or more velocities add by vector addition. Ex: If a river flows 5 km/h east relative to the bank, and a boat travels 12 km/h east relative to the river, what is the velocity of the boat relative to the bank? 17 km/h Ex: If a river flows 5 km/h east relative to the bank, and a boat travels 12 km/h north relative to the river, what is the velocity of the boat relative to the bank?   You need to use Pythagorean Theorem. a2 + b2 = c2

Section 11.3 Acceleration What is acceleration? Acceleration is the rate at which velocity changes. Acceleration can be changes in velocity, changes in direction, or changes in both. Acceleration is a vector. The basketball constantly changes velocity as it rises and falls

Changes in Speed Acceleration can be a positive change in speed (increasing), or a negative change in speed (decreasing). (You feel acceleration in a car when you start moving after a red light.)  As the bus moves down the street at a constant speed, its acceleration is zero. An example of acceleration due to change in speed is free-fall. Free-fall- The movement of an object toward Earth solely because of gravity. Remember: Velocity is in meters per second (m/s). Acceleration is in meters per second per second (m/s2). Free-falling objects accelerate downward at 9.8 m/s2.

acceleration Constant Acceleration- A steady change in velocity. Velocity of the object changes by the same amount each second. Calculating Acceleration You calculate acceleration for straight-line motion by dividing the change in velocity by the total time. a = acceleration vi = initial velocity vf = final velocity t = total time a = change in velocity a = vf - vi total time t Constant acceleration during takeoff results in changes to an aircraft's velocity that are in a constant direction

Math practice 1.A car traveling at 10 m/s starts to decelerate steadily. It comes to a complete stop in 20 seconds. What is its acceleration? 2.An airplane travels down a runway for 4.0 seconds with an acceleration of 9.0 m/s2. What is its change in velocity during this time?

3. A child drops a ball from a bridge 3.A child drops a ball from a bridge. The ball strikes the water under the bridge 2.0 seconds later. What is the velocity of the ball when it strikes the water? 4.A boy throws a rock straight up into the air. It reaches the highest point of its flight after 2.5 seconds. How fast was the rock going when it left the boy's hand?

Practice Accel problems Quiz on Accel HW: 2/6 Agenda Collect HW Go over the Quiz Practice Accel problems Quiz on Accel HW:

2/7 Do Now (do this in your packet) A tennis ball thrown to the sky has what velocity as it reaches it’s highest point? What is the acceleration of gravity on the ball at the highest point (give a #)? What is the acceleration of gravity on the ball as it starts to fall back to earth (give a #)?? Which will have a higher acceleration of gravity: a tennis ball, or a bowling ball?

Practice Accel problems Quiz on Accel Finish Circular Accel 2/7 Agenda Practice Accel problems Quiz on Accel Finish Circular Accel Review of graphing HW:

a= Vf= Vi= t= a = ΔV t a = Vf - Vi 5. A car is moving from rest and attained a velocity of 80 m/s. Calculate the acceleration of the car after 5 s? a= Vf= Vi= t= a = ΔV t a = Vf - Vi

a= Vf= Vi= t= a = ΔV t a = Vf - Vi 6. Determine the acceleration of a coaster which moves with a velocity of 10 m/s, after 2s its velocity is increases to 26 m/s. a = ΔV t a = Vf - Vi a= Vf= Vi= t=

a= Vf= Vi= t= a = ΔV t a = Vf - Vi 7. A bus accelerates from 25 km/hr to 50 km/hr in 30 seconds. What is its acceleration? a= Vf= Vi= t= a = ΔV t a = Vf - Vi

a= Vf= Vi= t= a = ΔV t a = Vf - Vi 8. A ball is thrown straight up in the air. If it takes the ball 2 seconds to reach its maximum height, what is the initial velocity? a= Vf= Vi= t= a = ΔV t a = Vf - Vi

a= Vf= Vi= t= a = ΔV t a = Vf - Vi 9. A ball rolls off the table and hits the floor in .7 seconds. How fast is the ball moving just before it hits the floor. a = ΔV t a = Vf - Vi a= Vf= Vi= t=

Changes in Direction Acceleration isn’t always the result of changes in speed. During a merry-go-round, the speed is constant but the direction changes. When you ride on a carousel, you accelerate because of the changing direction.

Changes in Speed and Direction Speed and direction changes when driving on a curved road or when riding a roller coaster. A roller coaster produces acceleration due to changes in both speed and direction

Effect of acceleration of gravity… Roller coaster Animation: https://www.google.com/search?q=circular+acceleration&safe=strict&espv=2&biw=1280&bih=9 19&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiGuIXP7erKAhXGmoMKHfHPDo4Q_AUIBigB#safe= strict&tbm=isch&q=circular+acceleration+roller+coaster+loop&imgrc=2XbEpqVrjsI3eM%3A Velocity graph + (forward) (Reverse) -

Phet simulator https://phet.colorado.edu/sims/html/forces- and-motion-basics/latest/forces-and-motion- basics_en.html

Next class…

Graphs of Accelerated Motion The slope of the speed-time graph is acceleration. Speed-Time Graphs Linear graph- the displayed data form straight-line parts. Slope = acceleration.

Speed-time Graphs The horizontal part of the graph shows a biker's constant speed. The part of the graph with negative slope shows negative acceleration as the mountain biker slows to a stop.

Distance-Time Graphs Accelerated motion is represented by a curved line in a distance-time graph. A distance-time graph of accelerated motion is a curve