Can you read what Mr Porter has written in your books?

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Do now! Can you copy this please? Speed and velocity Velocity is speed and DIRECTION. It is a vector quantity. “My velocity was 5 m/s NORTH.”

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Can you read what Mr Porter has written in your books?. Falling!. Imagine a dog being thrown out of an aeroplane. Woof! (help!). Force of gravity means the dog accelerates. To start, the dog is falling slowly (it has not had time to speed up). - PowerPoint PPT Presentation

Transcript of Can you read what Mr Porter has written in your books?

Page 1: Can you read what Mr Porter has written in your books?

Do now!Can you copy this please?

Speed and velocity

Velocity is speed and DIRECTION. It is a vector quantity. “My velocity was 5 m/s NORTH.”

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“Cool Runnings”

questions for homework.

Due Thursday 28th

September

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Acceleration

speed

time

a = v – u

t

(v= final speed, u = initial speed)

v

u

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Acceleration (m/s2)

acceleration = change in speed time taken

a = v – ut

a = acceleration (m/s2)v = final speed (m/s)u = initial speed (m/s)t = time taken (s)

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Getting faster? (accelerating)

speed

time

The area under the graph gives the distance travelled

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Do now!

• Can you make your Seed Spinners using the instructions?

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Falling!

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Imagine a dog being thrown out of an aeroplane.

Woof! (help!)

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Force of gravity means the dog accelerates

gravityTo start, the dog is falling slowly (it has not had time to speed up).

There is really only one force acting on the dog, the force of gravity.

The dog falls faster (accelerates) due to this force.

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Gravity is still bigger than air resistance

gravity

As the dog falls faster, another force becomes bigger – air resistance.

The force of gravity on the dog of course stays the same

The force of gravity is still bigger than the air resistance, so the dog continues to accelerate (get faster)

Air resistance

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Gravity = air resistanceTerminal velocity

gravity

As the dog falls faster and air resistance increases, eventually the air resistance becomes as big as (equal to) the force of gravity.

The dog stops getting faster (accelerating) and falls at constant velocity.

This velocity is called the terminal velocity.

Air resistance

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Gravity = air resistanceTerminal velocity

gravity

As the dog falls faster and air resistance increases, eventually the air resistance becomes as big as (equal to) the force of gravity.

The dog stops getting faster (accelerating) and falls at constant velocity.

This velocity is called the terminal velocity.

Air resistance

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Terminal Velocity

The dog will continue to fall at constant speed (called the terminal speed) until………….

gravity

Air resistance

air resistance = gravity

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Terminal Velocity

gravity

Air resistance

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Oooooops!

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Falling without air resistance

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Falling without air resistance

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Falling without air resistance

gravity

This time there is only one force acting in the ball - gravity

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Falling without air resistance

gravity

The ball falls faster….

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Falling without air resistance

gravity

The ball falls faster and faster…….

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Falling without air resistance

gravity

The ball falls faster and faster and faster…….

It gets faster by 10 m/s every second (10 m/s2)

This number is called “g”, the acceleration due to gravity.

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Falling without air resistance

gravity

Without air resistance objects fall faster and faster and faster…….

They get faster by 10 m/s every second (10 m/s2)

This number is called “g”, the acceleration due to gravity.

Can you copy the words please?

Where did I come from?

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Falling without air resistance?

speed

time

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Falling without air resistance?

speed

time

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Falling without air resistance?

speed

time

Gradient = acceleration = 10 m/s2 (9.81)

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Falling with air resistance?

speed

time

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Falling with air resistance?

speed

time

Terminal speed

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Let’s do an investigation

Investigating the terminal velocity of a

cupcake case.

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Do now – copy this!

• The gradient (rise over run) of a speed/time graph gives the acceleration.

• The area under a speed/time graphs gives the distance travelled.

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TEST!

• Monday 9th October• Everything we have done so far this year

(speed and speed/time graphs). • ALL LESSON POWERPOINTS are on

www.mrsimonporter.wikispaces.com• Can you also finish the sheets we have

done this lesson?

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“Ticket to exit”?!