Do Now!

• Can you talk to the person next to you about what we did last lesson?

Do Now!

A reminder

A reminder

Average speed = distance travelled time taken

S tdx

Examples

A man runs 99 m in 11 seconds. What is his speed?

Examples

A man runs 99 m in 11 seconds. What is his speed?

Speed = distance/time = 99/11 = 9 m/s

Another example

A dog runs at a speed of 3 m/s for two minutes. How far does he run?

Another example

A dog runs at a speed of 3 m/s for two minutes. How far does he run?

Distance = speed x time = 3 x 120 = 360 m

Another example!

A car travels at 60 km/h and covers a distance of 300 km. How long did it take?

Another example!

A car travels at 60 km/h and covers a distance of 300 km. How long did it take?

Time = distance/speed = 300/60 = 5 hours

Do now!Can you discuss with the person next to you what we

learnt (hopefully!) last lesson?

Distance against time graphs

distance

time

Let’s go on the corridor!

Let’s quietly and sensibly go in the corridor.

You’ll need a pencil and a

piece of paper.

Distance/time graphDistance /m

0 2 4 6 8 10 12 14 16

Time (slow)/s

0 2.2 4.0 5.6 7.4 9.0 11.0 12.9 14.6

Time (fast)/s

0 1.5 2.0 3.2 4.1 4.9 5.9 7.1 8.0

Distance/m 18 20 22 24 26 28 30 32

Time (slow/s 14.5 17.3 18.9 20.9 23.9

Time (fast)/s 8.4 9.7 10.6 12.1 12.8

distance

time

No movement?

distance

time

No movement

distance

time

Constant speed?

distance

time

Constant speed

distance

time

Constant speed

distance

time

The gradient of this graph gives the speed

Constant speed

distance

time

Δy

Δx

Gradient = Δy/Δx

Constant speed

distance

time

How would the graph look different for a faster constant speed (walking to

Physics)?

Constant speed

distance

time

fast

Constant speed

distance

time

fast

How would the graph look different for a slower constant

speed (walking to French)?

Constant speed

distance

time

fast

slow

Constant speed

distance

time

fast

slow

The gradient of the graph gives

the speed

Let’s go on the corridor!

Quietly and sensibly!

You’ll need a pencil and your

books

Distance/time graph - acceleration

Distance /m

0 2 4 6 8 10 12 14 16 18

Time/s 0 3.5 4.8 6.1 7.2 7.6 8.4 9.1 9.4 9.8

Distance/m 20 22 24 26 28 30 32

Time/s 10.0 10.4 11.2 11.0

Do now!Can you read Mr Porter’s

comments in your books?

Getting faster? (accelerating)

distance

time

Getting faster (accelerating)

distance

time

Examples

distance

time

A car accelerating from rest and then hitting a wall

distance

time

A car accelerating from stop and then hitting a wall

distance

time

Do now! Can you do the worksheet “Distance –

time graphs”?

Write the answers in your books, NOT on

the sheet.

Do now!Can you find

the “Cool Runnings”

results table?

Cool Runnings!

Speed against time graphs

speed

time

Speed against time graphs

speed

time

No movement?

speed

time

No movement

speed

time

Constant speed?

speed

time

Constant speed

speed

time

Constant speed

speed

time

How would the graph look

different for a faster constant

speed?

Constant speed

speed

time

fast

Constant speed

speed

time

fast

How would the graph look

different for a slower constant

speed?

Constant speed

speed

time

fast

slow

Getting faster? (accelerating)

speed

time

Getting faster? (accelerating)

speed

time

Constant acceleration

Getting faster? (accelerating)

speed

time

The gradient of this graph gives the acceleration

Acceleration

speed

time

a = v – u

t

(v= final speed, u = initial speed)

v

u

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)

Can you copy this please?

Getting faster? (accelerating)

speed

time

The area under the graph gives the distance travelled

Example:

speed

time

A dog falling from a tall building (no air resistance)

speed

time

A dog falling from a tall building (no air resistance)

speed

time

What does this area represent?

A dog falling from a tall building (no air resistance)

speed

time

Area = height of building

Be careful!

distance

time

speed

time

No movement

distance

time

speed

time

Constant speed

distance

time

speed

time

Area under graph = distance travelled

gradient = speed

Constant acceleration

distance

time

speed

time

Area under graph = distance travelled

Gradient = acceleration =

a = (v-u)/t

Stick them in!

Cool Runnings – the worksheet!

These questions are to be

finished for homework. Due next Friday 25th

September

“Ticket to exit”?!