Aim: What is the difference between speed & velocity?

Do Now: What is motion?

Homework: Read pgs 70 – 73 in textbook & Answer Ques. 1 & 2 on pg 72 (Practice Problems) – Write out Formula, Plug in #’s, Calculate & Give Units

Date: 10/15/2007 Monday

What is motion? • A change in position over a certain amount of time or,

• The movement of an object

What is speed? • The rate at which an object moves

(how fast or slow)

How can speed be calculated?

Speed = Distance

Time

S

D

T

1) Carl Lewis runs a 100 meter race in 10 seconds. What is his average speed?

Avg. Speed = Total distance/Total Time

Avg. Speed = 100 m/10 sec

Avg. Speed = 10 m/s

2) How much time does it take for a cheetah to travel 84 meters at a speed of 28 m/s?

Time = distance/speed

T = 84 m

28 m/sT = 3 sec.

3) What distance does a jogger go if she runs with a speed of 160 m/min for 20 minutes?

Distance = speed x time

D = (160 m/min) (20 min)

D = 3,200 m

What information does a Distance vs. Time Graph show?

Smith’s Trip to Albany

Distance (km) Time (hr)

50100150200

1234

200

150

100

50

1 2 3 4

DISTANCE(km) TIME (hours)

*Constant Speed:speed that stays the same

What information does a Distance vs. Time Graph show?

Brown’s Trip to Albany

Distance (km) Time (hr)

100100150200

1234

200

150

100

50

1 2 3 4

DISTANCE(km) TIME (hours)

*SpeedChanges

What is velocity? A measure of both speed & direction

Example: An automobile travels 80 km Northin 2 hrs. What is the avg. speed of the car? What is the avg. velocity?

V = D T

V = 80 km 2 hr

Avg. speed = 40 km/hr

Avg. velocity = 40 km/hr North

Aim: 1. What does a distance vs. time graph show? 2. How do velocities add & subtract

from each other?Do Now: 1. Take out homework.

2. What is the slope of a distance vs. time graph equal to?

Homework: Handout (A Speedy Journey)

Date: 10/28/2007 Friday

20 km (40 km – 20 km)0.5 h or 30 min

40 km (80 km – 40 km)1.5 hrs.

5. What is car B’s avg. speed during the first part of this trip?Avg. S = T. Dist.

T. TimeAvg. S = 40 km

0.5 hrAvg. S = 80 km/hr

6. How fast did cars A & B go together?Avg. S = T. Dist.

T. TimeAvg. S = 40 km

1 hrAvg. S = 40 km/hr

12 km / 20 s = 0.60 km/s 20 km / 30 s = 0.67 km/s

30 km / 40 s = 0.75 km/s 56 km / 60 s = 0.93 km/s

A = VF – VI

time

A = 0.67 – 0.60 10 .007 km/s2

A = 0.93 – 0.75 20 .009 km/s2

NO

Can velocities add together?

Yes, but only if they’re moving in the same direction

Example: If you are paddling a boat South at 5 m/s & the stream is moving at 8 m/s South:

Are their velocitiesadding together?

Your boat will move at:13 m/s South

Can velocities subtract from each other?

Yes, but only if they’re moving in the opposite direction

Example: If you are paddling a boat South at 10 m/s & the stream is moving North at 12 m/s:

Your boat will move:2 m/s North

6 m/s Right

10 m/s Right

16 m/s Right+

-

=10 m/s Right

14 m/s Left 4 m/s Left=

What does each picture show?

Velocities adding together

Velocities subtracting

Aim: Lab: Measuring the Speeds of People Walking

Do Now: 1. Take out homework.

2. Read over lab

3. Answer ques. next slide.

Homework: Complete Lab

Date: 10/17/2006 Wednesday

Aim: How can we calculate acceleration?

Do Now: 1. Take out Lab & Motion Note-packet

2. Complete Review Questions on pg 6 in your note-packet

Homework:Handout

All 4 cars are moving at constant speed

Avg. Speed = T. Dist./T. Time__________= 250 km/1 hr250 km/hr

#1#4

#1None

What is acceleration?

• The rate at which the velocity of a moving object increases

What is the mathematical formula for acceleration?

Acceleration =change in velocity

time

OR

a = vfinal – vinitial

t

1) What is the acceleration of an ice skater who changes velocity from 5 m/s north to 15 m/s north in 5 seconds?

a = 2 m/s2 North

a = vfinal – vinitial

t

a = 15 m/s – 5 m/s

5 s

2) How quickly would a race car accelerate if its velocity changed from 0 to 32 m/s in 4 seconds?

a = 8 m/s2

a = vfinal – vinitial

t

a = 32 m/s – 0 m/s

4 s

What is deceleration?

• The rate at which the velocity of a moving object decreases

What information does a Velocity vs. Time Graph show?

Smith’s Trip to Albany

Velocity (m/s) Time (s)

7142128

1234

28

21

14

7

1 2 3 4

VELOCITY(M/S) TIME (hours)

*Constant acceleration

What is the motionof a freely fallingobject?

Any object falling near the surfaceof the earth will accelerate at a rate of 9.8 m/s2 due to the pull of gravity.

Aim: What is Momentum?

Do Now: Prepare for Motion Quiz

Homework: Study for next week’s Exam on Motion & Forces

Date: 10/19/2007 Friday

•Quiz (Motion)

What is momentum?

• The mass of an object multiplied by its velocity, which determines how difficult it is to stop the object.

• The greater the momentum = greater energy the object has

What is the mathematical formula for momentum?

momentum = mass x velocity or p = mv

Aim: 1. What is Force?

Do Now: 1. What 2 things does momentum depend upon?

2. What are units of momentum?

Homework: Study for a Quiz on Forces.

Date: 10/22/2007 Monday

What is a Force?

A push or a pull that one object exerts on another.

Ex) A tow truck pulls a car, The wind pushes a flag,

Gravity & Friction

What is a Newton?

The unit used to measure forceForce = Mass X Acceleration

1N = kg.m/sec2

What are some examples of a force?

What is gravitational force?

1. The attractive force between objects

2. Depends on the masses of the objects and the distance between them

As mass increases, gravitational pull increases

As distance increases, gravitational pull decreases

50 kg 10 kg

Where is the Gravitational Pull the greatest?

1.

2.10 kg10 kg

10 m

10 m

10 kg

Where is the Gravitational Pull the greatest?

1.

2.10 kg10 kg

10 m

20 m

10 kg

What is weight? The weight of an object is equal to the gravitational force exerted by Earth (9.8m/s2) on an object

Where will you weigh more: on theEarth or on the Moon? Why?

What are balanced forces?

Forces on an object that are equal in size & opposite in direction

The net force is zero because the two forces cancel each other out

-= 0

What are unbalanced forces?

Unequal forces working against each other produces motion in the direction of the larger force.

10N

4N- =

6N

*In Opposite Directions,Forces Subtract

Aim: 1. What is Newton’s First Law of Motion?

Do Now: Prepare for a Quiz.

Homework: Read pgs 98 – 103 &

Ans. Ques. (1-4 & 6-7) on pg 103 (self-check)

Date: 10/23/2007 Tuesday

• Quiz (Momentum & Forces)

Newton’s Laws

MMoottiioonn of

What is Newton’s 1st Law of Motion?

The Law of Inertia

1. Objects at rest tend to stay at rest unless acted upon by an unbalanced force.

2. Objects in motion tend to remain in motion (in constant velocity, along a straight path) unless acted upon by an unbalanced force. (such as friction)

This is what happens when your not wearing a seatbelt. Since the car is in motion you are also in motion, and when the wall stops the

car.You continue to be in motion and fly forward.

When the truck is stopped by the car. The ladder continues in

motion.

What is inertia?

The tendency of an object to resist a change in motion.

Inertia is related to an objects mass: the more mass an object has the greater its inertia and the more difficult it is to change its motion.

Which would have more inertia an empty shopping cart or a full one?

Aim: 1. What are 3 types of friction?

Do Now: 1. Take out homework.

2. What is Newton’s First Law of Motion?

Homework: Read pgs 104-111 Ans. Ques. (1-4 &

6) on pg 111 (self check)

Date: 10/24/2007 Wednesday

What is friction? 1. Exists wherever 2 surfaces touch.

2. It’s a force that acts in the opposite direction to motion.

3. It causes moving objects to slow down & stop.

4. It always produces heat.

What types of friction are there?

1) Sliding Friction – When solid objects slide over each other.

2) Rolling Friction – Friction produced by wheels or ball bearings

3) Fluid Friction – The force exerted by a fluid (Lubricants such as grease & oil) change sliding friction into fluid friction and reduce the overall amount of friction.

What are some methods used to reduce friction?

Can friction be good?

Yes!

1. Lubricants such as oil, grease, lotion, water

2. Wheels (Rolling frictions is less than sliding friction)

3. Sand on a smooth surface

Pull

Right 7N

Pull

Left 2N (Friction)

In what direction is this object moving?What are 3 forces are acting on this object?

How can we decrease the friction?What is friction?

Aim: How do force, mass & acceleration relate to each other?

Do Now: 1. Take out homework.

2. Describe the 3 types of friction.

Homework: Study for tomorrow’s Quiz on Forces

Date: 10/25/2007 Thursday

What is Newton’s Second Law?

Force = Mass X Acceleration

Newton’s second law of motion explains how force and acceleration are related

What is the equation form of Newton’s second law?

F

M A

Which car will take a greater force to accelerate?

How much force is needed to accelerate a 1500kg car at a rate of 3 m/sec/sec?

Force = mass x acceleration

Force = 1500kg x 3 m/sec/sec

Force = 4500NF

M A

A hockey player shoots a puck with a force of 900 Newtons. The puck has a mass of 1.5kg. At what rate will the puck accelerate?

F

M A

Acceleration = Force

MassAcceleration = 900 N 1.5 kg

Acceleration = 600 m/s2

What is the relationship between force & acceleration?

As force increases, acceleration increases.

Direct Relationship

What is the relationship between mass & acceleration?

As mass increases, acceleration decreases.

Inverse Relationship

Aim: 1. What is Newton’s 3rd Law of Motion? 2. Quiz on Forces.

Do Now: Take out note-packet.

Homework: Study for Tuesday’s Motion/Forces Exam

Date: 10/26/2007 Friday

What is Newton’s Third Law of Motion?

For every action there is an equal and opposite reaction.

Newton's third lawNewton's third law. . The skaters' forces on The skaters' forces on each other are equal ineach other are equal in magnitude, and inmagnitude, and in

opposite directionsopposite directions

• Newton’s Final Quiz

STOP

• Quiz Section Beyond This Point

Quiz (Motion))

1. Velocity = ________ & ________.

2. A change in position over time is known as _________.

3. If I rollerblade 10 meters in 2 seconds, how fast am I moving?

4. If a car goes 20 km/hr in 0.5 hours how far did it travel?

5. A car went from stop to 30 m/s in 5 seconds. What was the rate of acceleration?

GO ON….

These graphs show:6.

7.

GO ON….

8. Which car is moving the fastest?

9. What pulls everything towards the earth at a rate of 9.8 m/s2?

10.What tools are used to calculate speed? Stop!!

Quiz (Momentum &Forces))

1. Momentum = ________ & ________.

2. A force = a ________ or a _________.

3. Units of force = ______________

4. As distance increases, gravitational pull ___________.

5. A book is resting (no motion) on the desk & is pushing down with a force of 3N. The desk is pushing up with a force of ________N.

STOP!!

What is a force?

What are balanced forces?

What do unbalanced forces cause?

What does friction create?

A force gives off ?

What are units of force?

What is a force that opposes motion?

STOP!!!