Do now 4/10

Review: Write a hypothesis for the following problem:

I want to know if using natural toothpaste makes my

teeth white than using regular toothpaste.

Exam make-ups

• Tomorrow after school in my room• Grades close Friday

Science Fair

• Report draft is due written neatly by Friday April 13, 2012

• Final draft due typed with display board no later than April 18th, 2012

• Science Fair is April 19-20th

Plan for this week:

• Tuesday: Science Fair• Wednesday: Newton’s 1st Law• Thursday: Newton’s 2nd Law• Friday- Science Fair draft due- work on display

boards in class

DO NOW 4/11

• Anne drops a plastic fork and a metal fork of the same size and shape at the same time. Which one do you think will hit the ground first? Why? ANSWER IN TAG OR RECEIVE ZERO POINTS

Reminders

• Science fair report draft due Friday • Grades close Friday• Make up exam today at 3:45

Agenda

• Do now 3 min• Notes – 5 min• Practice notes – 2 min• Activities – 10 min• Ip – 5 min• Closing 2 min

Topic: Newton’s 1st Law (Inertia)

• 4 slides of notes• Write Questions as you go, I will give examples

1ST LAW OF MOTION (LAW OF INERTIA)

• Newton’s 1st Law says that an object at rest will remain at rest and an object in motion will remain in motion unless an unbalanced force acts upon it.

Questions Notes

• What is Newton’s 1st Law and how is it related to inertia?

• Newton’s 1st Law says that an object at rest will remain at rest and an object in motion will remain in motion unless an unbalanced force acts upon it.

1ST LAW• Also known as the LAW

OF INERTIA!• Inertia: The resistance

of any object to a change in its motion, whether its moving or not.

• More Mass = More Inertia

• Less Mass = Less Inertia

These pumpkins will not move unless acted on by an unbalanced force.

Questions Notes

• What is inertia and how is it related to mass?

• Inertia: The resistance of any object to a change in its motion, whether its moving or not.

• More Mass = More Inertia• Less Mass = Less Inertia

1ST LAW examples • Golf Ball - once

airborne it would never stop!

unless acted on by anunbalanced force

(gravity and air – fluid friction)

Questions Notes

• Why does a golf ball hit into the air keep going if it has inertia?

• Once a golfball is n the air it would never stop unless another force acts on it- like gravity

1ST LAW

• Unless acted upon by an unbalanced force, this golf ball would sit on the tee forever.

Questions Notes

• Unless acted upon by an unbalanced force, this golf ball would sit on the tee forever.

2 minutes practice notes

Newton’s 1st Law

• You are driving in a car with no seat belt on. You see a family of ducks and slam on your brakes to avoid hitting them. Since you are not wearing your seat belt, you fly out of the car (remain in motion) until you hit the ground (an unbalanced force).

AHH!

Ouch

In motion… At rest…

• Answer the following question with a partner at your table Be prepared to share when called on. (LIBRARY VOICES, 1 minute).

• You are being chased through the wilderness by a gigantic elephant. The elephant’s mass would be threatening, however, if you zigzagged, the elephant’s mass would work to your advantage. Why is that? Explain using the word “inertia”.

• Newton’s Law Activity• You have 7 minutes, at your table, in

library voices.

Complete the activity at your table and answer the questions in COMPLETE SENTENCES

1. Newton’s first law is working because it shows how an object can be affected by something else. That shows the part “an object in motion stays in motion until acted on by an apposing force.” The force of the washers pushing the other washers in the greater force

2. in this quick experiment when you hit he washers against washers , they move . In newton's laws it says it wont move unless an object acts upon 1`it in this case

3. The first stack of washers that is being flicked is a balanced force and the second stationary one is balanced. When one stack is flicked by your finger the applied force then makes it unbalanced and when the second stack is hit by the first one it also becomes unbalanced until gravity stops it.

4. Our objects were at rest and remained at rest which relate to newton b/c the object will stay @ motion or @ rest unless any type of force is acted on it

• the objects are moved determined by the force applied

• If something is at rest, it stays at rest/ in motion stays at motion

• The amount of washers flicked is the amt that get replaced

• Objects are moved determined by force applied

Answer the following question with a partner at your table Be prepared to share when called on. (LIBRARY VOICES, 1 minute).If you slide a book across a

table, it slides to a rest position. Use Newton’s 1st Law to explain Why this

happens

The book comes to a rest because of the presence of a force - that force being the force of friction - which brings the book to a rest position.

• In the absence of a force of friction, the book would continue in motion with the same speed and direction - forever! (Or at least to the end of the table top.)

INDEPENDENT PRACTICE

• SILENT AND ALONE OR RECEIVE A DETENTION• YOUR WORK MUST BE INITIALED BY ME

BEFORE CLASS ENDS• Read pages 80-81 until newton’s second law

and answer questions 15 and 16 on page 85

Closing:Explain how Newton’s 1st Law is

demonstrated in the graphic below.

Do now 4/12Use Newton’s First Law to explain the

“magic trick” in this video.

USE YOUR NOTES

Newton’s First Law

“An object at rest remains at rest, and an object in motion continues in motion with constant velocity (that is, constant speed in a straight line) unless the object

experiences a net external force.”

This is also known as the Law of Inertia.

Agenda

• Do now (5 min)• Notes (2 min)• Whole Class Practice (15 min)• Practice in groups (10 min)• IP (10 min)• Closing (5 min)

Topic: Newton’s 2nd Law (F=MA)

* Force is equal to mass times acceleration

* An object will accelerate in the direction of any net force applied to it.

* The greater the force, the greater the acceleration.

* The greater the mass, the slower the acceleration.

* Or, simply put F=ma.

Newton’s Second Law

Things move faster and farther when they are pushed harder.

Things move in the direction pushed unless another force changes the direction

Newton’s Second Law, IOW

F = maForce = Mass (Acceleration)

Newton = kg (m/s2)

Something with less mass needs less force to move!

Smart car- Mass: 730 kg

Hummer- Mass: 2200 kg

How much force does it take to accelerate a hummer and a smart car 10m/s/s? Which requires less force?

Smart car- Mass: 730 kg

Hummer- Mass: 2200 kg

If you don’t have a lot of money for gas (force) what car is the best option?

PRACTICE PROBLEMS:USE WIPE OFF SHEET

An automobile with a mass of 1000 kilograms accelerates when the traffic light turns green. If the net force on the car is 4000 Newtons, what is the car’s acceleration?

A 100-kg crate, sliding on the floor, is brought to a stop by a 25-N force. What is the deceleration of the crate?

Calculate the acceleration of a 2x103 kg, single-engine airplane just before takeoff

when the thrust of its engine is 500 N.

Calculate the acceleration of a 3.0x106 kg jumbo jet just before takeoff when the thrust for each of its four engines is 3.0x105 N.

A football is kicked with a force of 15.5 N and accelerates at 36.1 m/s2 during the brief microseconds it is in contact

with the kicker’s foot. What is the mass of the ball?

A rifle fire bullets with a force of 500 Newtons, if the acceleration of the bullet in the barrel of the gun was approximately 2.5x104 m/s2, what is the mass of the

bullet in grams?

What is the minimum force with which a person with a mass of 100

kg must push in order to do a push-up?

(hint: you must overcome gravity)

An occupant of a car has a chance of surviving a crash if the deceleration during the crash is not more than 30 g. Calculate the force on a 70-kg person decelerating at the same rate.

A 45 kg kid goes down a half-pipe that is 4.3 meters long in 0.8

seconds. What is the net force acting on him?

An Olympic diver weighing 63.5 kg jumps off of the 30 meter board. She lands in the water at a velocity of 24.26 m/s. What is the net force acting on her?

http://www.history.com/shows/the-universe/videos/beyond-the-big-bang-sir-isaac-newtons-law-of-gravity

CLOSING

Describe F=MA in your own words. Use an example.