Transcript Lesson 10 Stopping distances

In pairs can you CAREFULLY
go through the exam. Can you
then write in your book the title
5 Things I have learnt from the
exam
and then list 5 things you have
learnt!
Last lesson
Falling!
Gravity = air resistance
Terminal speed
Air resistance
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 speed.
gravity
This velocity is called the terminal speed.
Falling without air resistance
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.
gravity
Falling without air resistance?
distance
time
Falling without air resistance?
speed
time
Falling without air resistance?
speed
Gradient = acceleration = 9.8 m.s-2
time
Falling with air resistance?
distance
time
Falling with air resistance?
Terminal speed
speed
time
Today’s lesson
Stopping
distances
Stopping distances
The distance a car takes to stop is called
the stopping distance.
Two parts
The stopping distance can be thought of in
two parts
Stopping distances
Thinking distance is the distance traveled whilst
the driver is thinking (related to the driver’s
reaction time).
Thinking distance
This is affected
by the mental
state of the driver
(and the speed of
the car)
Braking distance
This is the distance traveled by the car
once the brakes have been applied.
Braking distance
This affected by the speed and mass of
the car
Braking distance
It is also affected by the road conditions
Braking distance
And by the condition of the car’s tyres.
Typical Stopping distances
YouTube - Top Gear 13-5: RWD Braking Challenge
YouTube - Think! - Slow Down (Extended) (UK)