# 6.4 Braking and collisions VWO

6.4 Braking and collisions
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Slide 1: Tekstslide
NatuurkundeMiddelbare schoolhavo, vwoLeerjaar 2

In deze les zitten 19 slides, met interactieve quizzen en tekstslides. Lesduur is: 30 min

## Onderdelen in deze les

6.4 Braking and collisions

#### Slide 1 -Tekstslide

In traffic you always have to able to stop in time without having a collision.

#### Slide 2 -Tekstslide

What factors will influence the braking distance?
A
Mass of the car
B
Braking force
C
Speed of the car
D

#### Slide 3 -Quizvraag

The higher the initial speed,
the longer the braking distance.

#### Slide 4 -Tekstslide

The greater the mass of the vehicle,
the longer the breaking distance.

#### Slide 5 -Tekstslide

If the road is slippery you have to brake slowly, othewise the car will slip.

#### Slide 6 -Tekstslide

Braking distance

Depends on:

• Initial speed;
the faster you are going, the greater the braking distance
• Total mass;
the greater the mass the greater the braking distance
• Braking force;
the harder the brakes are pressed the shorter the braking distance

#### Slide 7 -Tekstslide

Stopping distance = reaction distance + braking distance

#### Slide 8 -Tekstslide

Reaction distance

Reaction distance  =  reaction time  x  velocity

The reaction time in normal conditions is around 1.0 second.

#### Slide 9 -Tekstslide

Braking distance
Reaction distance

#### Slide 10 -Sleepvraag

A horse runs to the finishline at 39.6 km/h. The drivers reaction time is 0.2 s. The braking distance is 22.8 m. Determine the stopping distance.

Formulas:
stopping distance = reaction distance + braking distance
reaction distance = reaction time x velocity

#### Slide 11 -Tekstslide

A horse runs to the finishline at 39.6 km/h. The drivers reaction time is 0.2 s. The braking distance is 22.8 m. Determine the stopping distance.

#### Slide 12 -Open vraag

v = 39.6 km/h = 11 m/s (39.6 / 3.6)
t = 0.2 s (reaction time)
braking distance = 22.8m

stopping distance = reaction distance + braking distance

reaction distance = v x t = 11 x 0.2 = 2.2 m
stopping distance = reaction distance + braking distance
stopping distance = 22.8 + 2.2 = 25m

#### Slide 13 -Tekstslide

initial speed and braking distance
If the speed is n times bigger,
the braking distance becomes n2 times longer.
v = 10 m/s
s = 5 m
v = 20 m/s
s = 20 m
v = 30 m/s
s = 45 m
n= 2= 4
braking distance = 4 * 5 = 20 m
n2 = 32 = 9
braking distance = 9 * 5 = 45 m

#### Slide 14 -Tekstslide

If the initial velocity is 10 m/s the braking distance is 5 m. What is the braking distance with an initial velocity of 90 km/h?

#### Slide 15 -Open vraag

If the initial velocity is 10 m/s the braking distance is 5 m. What is the braking distance with an initial velocity of 90 km/h?

v = 90 km/h = (90/3.6) m/s = 25 m/s
n = 25/10 = 2.5
n= 2.52 = 6.25
braking distance = n2 x old braking distance
braking distance = 6.25 x 5
braking distance = 31.25 m

#### Slide 16 -Tekstslide

If the initial velocity is 10 m/s the braking distance is 5 m. What is the initial velocity with a braking distance of 80 m?

#### Slide 17 -Open vraag

If the initial velocity is 10 m/s the braking distance is 5 m. What is the initial velocity with a braking distance of 80 m?
braking distance = 80 m
braking distance = n2 x old braking distance
80 = n2 x 5
n2 = 80 / 5 = 16
n = √16 = 4
initial velocity = 4 * 10 = 40 m/s

Homework
5.4 Exercises
VWO: 1 until 12