original hw percent original hw grade in class test grade new hw grade 76158315 76157015 76156212...

Original HW Percent

Original HW Grade

In Class Test Grade

New HW Grade

76 15 83 15

76 15 70 15

76 15 62 12

100 15 73 0

Old Homework Assignments

Make Up Test!

Bellringer

Protractors!

Prepare for the Regents Exam

Objective

1.35 weeks from today◦ June 17th @12:15pm

I need my rulers and protractors back.

Get a calculator

Review Classes

Regents Exam

Return them.

Textbooks

Final Homework due next Wednesday

Mark any questions that confuse you, and then see me as soon as possible.

Review Homework

It’s Crunch Time Baby!

Who will be remembered forever in the Physics Hall of Fame?

2015: 71%

2014: 74%

The Practice Regents

Must see me after school at least twice next week.

Mod 2:◦ Franco, Maddie, Molly, Mike, Chris, Ana, Shannon,

Olivia Mod 8:

◦ Adam, Kendra, Ian, Brenna, Steven, Nick, Megan, Colin, John, Kaylee

Physics Review

1. Must correct every question you lost credit on.2. Must show your work for every correction.3. When complete you must identify the three

areas/topics that you need the most improvement on and how you plan on improving them.

4. You must hand them in to me during one of my free mods or after school.

Test Corrections: Due Tuesday

Old Papers

A scalar quantity is a unit that has a magnitude but no direction.

A vector quantity is a unit that has both a magnitude and direction

Scalar vs Vector

The Big 3 of Kinematics

1 Dimensional Kinematics

What is the acceleration due to gravity on Earth?

What is an object’s initial velocity if it is dropped from rest?

What is an object’s velocity at the top of its path when it is thrown straight up?

Kinematics

Now let’s put it to work! If a skydiver in free fall has an initial velocity

of -15m/s what will her final velocity be after 13 seconds?

Or 142.53m/s towards Earth

Now you try (3 minutes) You are drag racing a funny-car that can accelerate

13m/s^2. If it takes you 5.3 seconds to finish the race, what is your final velocity?

A foul ball is hit perfectly straight up into the air. It has an initial upward velocity of 15m/s and is in the air for 3.0581 seconds. What is it’s final velocity right before it hits the ground?

68.9m/s

-15m/s

Now Let’s Put It To Work!! How far would a skydiver fall if he had an initial velocity

of zero meters per second and was in free fall near the surface of the Earth for 36 seconds? (Neglect air resistance)

So the skydiver would fall 6356.88m towards Earth

Now you try (3 minutes) How long would it take a 1997 Acura Integra LS to

travel 100m if its initial velocity is 0m/s and its maximum acceleration of 3m/s^2?

What is the rocket’s initial velocity if it accelerates constantly at 8m/s^2 and covers a distance of 57,750m in 120s?

8.2 seconds; fast for a human, but really slow for a car…or even an 18 wheeler

1.25m/s

Now Let’s Put It To Work!! What is the final velocity of hail ball that

fell 90 meters straight down from the heavens with an initial velocity of -3m/s?

Now you try (3 minutes) What is the final velocity of hail ball that fell 90 meters

straight down from the heavens with an initial velocity of 3.0m/s?

You hit a volleyball so that it moves with an initial velocity of 6m/s straight upward. If the volleyball starts from 2 meters above the floor, what will the volleyball’s velocity be right before it strikes the floor?

−42.13𝑚𝑠

-8.7m/s

Acceleration due to gravity

The acceleration due to gravity is constant and the only force acting on an object in free fall.

The time it takes an object to travel from the ground to it’s highest point, is the same time as it takes the object to fall back down from the same height.

All objects fall with the same acceleration.

Mass does not effect how fast an object falls!

Acceleration Due to Gravity

Just kinematics in two dimensions (x and y)

Remember only the time variable can be used in both dimensions

Projectile Motion

Dimension

Displacement (m)

Initial Velocity

(m/s)

Final Velocity

(m/s)

Acceleration

(m/s^2)

Time(s)

XY

Example A bullet is fired horizontally at 300m/s from

1.5m above the ground. How far down range does the bullet land? Ignore friction.

Dimension

Displacement (m)

Initial Velocity

(m/s)

Final Velocity

(m/s)

Acceleration

(m/s^2)

Time(s)

XY

Kahoot

Example A bullet is fired horizontally at 300m/s from

1.5m above the ground. How far down range does the bullet land? Ignore friction.

We need to find the hang time of the bullet and then use that to figure out the distance it traveled in that time:

Example We don’t have enough information to find the

hang time in the x-direction so we will have to find it in the y-direction instead.

t=.55s

Example Cont’d

Now use this time to see how far the bullet traveled horizontally. Total hang time is the same for the x and y directions

Dimension Displacement

(m)

Initial Velocity

(m/s)

Final Velocity

(m/s)

Acceleration (m/s^2)

Time(s)

X ? 300 300 0 0.55

Y -1.5 0 ? -9.81 0.55

Example Cont’d Use:

So the bullet travels 165.7m before hitting the ground

Another Example A cannonball is shot horizontally off of a cliff at an

initial speed of 150m/s. The cannon is 45m above the level ground at the bottom of the cliff. How far down range will the cannonball land? Ignore friction.

Try this one on your own!

Range :

Can we calculate where an object launched at an angle will land?

A punter punts the football with an initial velocity of 18m/s and at an angle of 58 degrees off of the field. Ignoring friction, what is the hang time of the this punt? FILL IN THE CHART!!!

Dimension Displacement

(m)

Initial Velocity

(m/s)

Final Velocity

(m/s)

Acceleration (m/s^2)

Time(s)

X ? ? ? 0 ?Y 0 ? ? -9.81 ?

Can we calculate where an object launched at an angle will land?

First we must find the Y-component of the initial velocity!

Can we calculate where an object launched at an angle will land?

A punter punts the football with an initial velocity of 18m/s and at an angle of 58 degrees off of the field. Ignoring friction, what is the hang time of the this punt? FILL IN THE CHART!!!

Dimension Displacement (m)

Initial Velocity

(m/s)

Final Velocity (m/s)

Acceleration (m/s^2)

Time(s)

X ? ? ? 0 ?Y 0 15.3 -15.3 -9.81 ?

The Punt Cont’d With the initial y-velocity we can calculate the

total hang time of the punt using:

Can we calculate where an object launched at an angle will land?

Dimension

Displacement (m)

Initial Velocity

(m/s)

Final Velocity (m/s)

Acceleration (m/s^2)

Time(s)

X ? ? ? 0 3.11

Y 0 15.3 -15.3 -9.81 3.11

The Punt Cont’d What is the total horizontal range of the

punt?◦ Use the chartDimen

sionDisplace

ment (m)

Initial Velocity

(m/s)

Final Velocity (m/s)

Acceleration (m/s^2)

Time(s)

X ? ? ? 0 3.11

Y 0 15.3 -15.3 -9.81 3.11

The Punt Cont’d Need to find the initial X-velocity first!

The Punt Cont’d Plug into the chart

Dimension

Displacement (m)

Initial Velocity

(m/s)

Final Velocity (m/s)

Acceleration (m/s^2)

Time(s)

X ? 9.5 9.5 0 3.11

Y 0 15.3 -15.3 -9.81 3.11

The Punt Cont’dNow find the total range of the football

Question! An airplane is carrying supplies for people

stranded on an island. If the pilot wants the supplies to land on the island when should he drop the package? Why?

A. Before he is above the islandB. When he is above the islandC. After he flew over the island

Which angle will maximize the height of a projectile?◦ 90

Which angle will maximize the range of a projectile?◦ 45

Which angle will maximize the hang time of a projectile?◦ 90

Which angle will minimize the hang time of a projectile?◦ 0

Launch Angle

Work on Regents Exam

Complete alone.

Highlight any questions you needed to use your notes for.

See me for help!

Classwork/Homework

Bellringer An airplane is carrying supplies for people

stranded on an island. If the pilot wants the supplies to land on the island when should he drop the package?

A. Before he is above the islandB. When he is above the islandC. After he flew over the island

Review Forces, Friction, and Kinematics

Objective

Corrections are due today

Final homework is due tomorrow

Homework

Net Force: All the force vectors added together.

Equilibrium: Net force is zero Newtons

Static Equilibrium: the object is not moving

Inertia: A property of mass

Forces and Friction

Netwon’s Three Laws1. An object in motion remains in motion unless

acted upon by an outside force2. F=ma3. Every action has an equal and opposite reaction

◦ Kinetic vs. Static

Forces and Friction

What happens to the normal force if you add more mass?

The Normal Force

The Lawn Mower

If Gary pushes the lawn mower a constant velocity with a force of 50N down the handle what is the magnitude of the force moving the mower forward? The handle is 50 degrees above the level ground.

50N

50

32.1Nmg

38.3

N

Fric.

Norm

al

Station Questions

Draw a circuit that has a battery, two resistors wired in parallel and an ammeter that measures the current going through only one of the resistors.

Bellringer

Get better at physics

Objective

Centripetal- “Center Seeking” Centripetal Acceleration = speed²/radius

◦ Or:

v = speed of the object r = radius of curvature

Uniform Circular Motion

Centripetal Force is a force that is directed towards the center of a circle that keeps an object in circular motion.◦ Why do you hit the car door when you turn?

What supplies the centripetal force that allows your car to go around turns?

UCM

If your speed is constant while you’re moving in a circle, how can you be accelerating?

Centripetal Force

Direction of Centripetal Force

Question My jeep and I have a mass of 1300 kg. If I

drive around a turn with a radius of 100 m at a speed of 17.5 m/s calculate the:1. The Centripetal Acceleration2. The Centripetal Force

3. What is providing the centripetal force?

Jeep beep1. ac = v2 / r

= (17.5 m/s)2 / 100m = 3.06 m/s2

2. Fc = mv2 / r

= (1300 kg)(17.5 m/s2) / 100 m = 3981.25 N

If your tires can supply a maximum centripetal force of 10,000N how can you increase your velocity around a turn?

Increase your radius

Trends

Page 162 of the textbook 12 13 14 15

Practice

Gravitation is one of the four fundamental forces.

It is only attractive. It pulls on both parties equally.

Newton’s Law of Universal Gravitation

Calculate the force of gravitational attraction between a 75 kg person and a 62 kg person that are 1.5 meters apart!

IS THIS TRUE LOVE????!?!?!?

True Love!

Is this what love is?

What would the force be if the two people were 3m apart?

True Love!

OR…

Where is the gravitational constant for a certain planet!

Gravitational Force

Page 185 8 10 11 13a 13b

Practice

Why is there gravity?

Einstein said it was because mass bends the four dimensional space-time that our universe is made of.

Sheet Demo

Gravity

What is the speed of sound in a vacuum?

Bellringer

Get better at physics

Objective

No special units just Unless otherwise stated, momentum is

conserved in collisionspbefore = pafter

pAi + pBi = pAf + pBf

mAvAi + mBvBi = mAvAf + mBvBf

Momentum

Example If you have a mass of 62 kg and you are

running at a constant velocity of 8 m/s what is your momentum

If your car has a mass of 2000kg and is parked what is it’s momentum?

Conservation of Momentum A 90 kg running back is running up field

with a constant velocity of 7 m/s. A 105 kg linebacker is running down field with a velocity of 6.5 m/s as he tackles the running back. After they collide find their total velocity.

pbefore = pafter

pRi + pLi = pRf + pLf

mRvRi + mLvLi = mRvRf + mLvLf

Basketball

Momentum Demos

Momentum and Force

How does the force on an object relate to its change in momentum?

Crash Test Dummies Why do we have crash test dummies?

http://www.youtube.com/watch?v=8adfGDQ-uRA

Crash Test Dummies What is a car’s momentum before a collision

with the wall?

What is a car’s momentum after a collision with the wall?

Is momentum of this system conserved?

Momentum and Time

How does the time of a collision relate to the change of momentum?

Tree Jumping Is it possible to jump out of a twenty foot tall

tree without hurting yourself?

Is it possible to jump out of a twenty foot tall tree and hurt yourself?

Do both systems have the same change in momentum?

Video Clips http://www.youtube.com/watch?v=aAhPaiajwDY

http://www.youtube.com/watch?v=WCQEYXG-3Nw

What is the difference? Why do hardcore parkour(ers?) not injure themselves when they fall long distances? Does gravity effect them differently?

The time of impact changes the force they feel.

Egg Toss Are eggs easy to break?

Impulse The impulse of a collision is the change in

momentum of the collision.

The change in momentum is equal to the force during the collision multiplied by the time of the collision.

Does a larger impulse always mean a larger force?◦ No! Time also controls the amount of force.

Which is a greater change in momentum on a 2kg object?A. Accelerating from 2m/s to 6m/sB. Having a net force of 12N for 0.75 seconds

Questions

Kinetic energy

Gravitational potential energy

Internal energy

Spring energy

Units are Joules

Energy

The total amount of mass-energy in a system is always conserved.

Mass-Energy can be transformed into a different form, but cannot be destroyed.

Conservation of Mass-Energy

When is GPE maximized?

When is KE maximized?

When is Q maximized?

How do you find the KE between its min and max?

The Pendulum Problem

If a 6.8kg bowling ball is 1.0m above its lowest point in its swing, what is its maximum velocity?

Question

Conservation of Energy

4.4m/s

Roller Coasters Magic Can Dropper Poppers Balloons Gasoline Nuclear Power Plants

Examples

Hooke’s Law Hooke’s Law states that a spring exerts a

force directly proportional to the distance it is stretched.

Spring Potential Energy Springs can also store potential energy

What happens to the potential energy of a spring as you compress or stretch it more and more?

It increases, until it becomes too much and breaks…

Test Your Might Draw bar graphs of

the Total Energy, Potential Energy, and Kinetic Energy of the red block – spring system for all four stage shown.

Work To understand this phenomena we need to

know more about work.

Work can be calculated two ways

F=Force (Newtons) d=displacement (meters)

You try! A hockey player uses a stick to exert a constant

4.50N force forward to a 105g puck sliding on ice over a displacement of 0.150m forward. How much work does the stick do on the puck? Assume friction is negligible.

W=0.675J Do you need the mass for this problem? Nope

Work Graphs Calculate the total work done using the

graph below.

Physics Teacher https://

www.youtube.com/watch?v=Z0iEUPFGLXI

Your thoughts?

Power Power is equal to the change in energy

divided by the time required for the change.

The units are J/s or Watts (W)◦ 1 Watt = 1 Joule of energy transferred in 1 second

Power It is written differently on your reference

table:

Stack of Books Either way I did 100J of work on the stack of

books. How much power did I exert if I completed the work in 2.0 seconds?

What about if it took me 45 seconds?

Doing work faster requires more power.

The “Variety” of Power A forklift can lift a 900N weight at 4 m/s.

How much power is it exerting?

Your car engine exerts a force of 5,000N over a distance of 30m in 5.0 seconds. How much power is it exerting?

Heavy Lifting The big guy can squat 180kg a distance of

0.8m in 2.2 seconds. The small guy can squat 85kg a distance of 1.0m in 1.2 seconds. Who is more powerful?

Big Guy = 642 Watts Small Guy = 695 Watts

Pick up old tests/homework/answer sheets from the back table.

Bellringer

Master physics

Objective

Rocket Time

Find a partner that has an internet machine.

Take out a calculator, reference table, and scrap paper.

Pick up a question booklet.

Kahoot