P8.1

Question 1

Equipment to measure the speed of a sprinter

Answer 1

• electronic timing
• measuring tape / TRUNDLE WHEEL
• pressure sensor to start + break laser beam to end

Question 2

Equipment to measure the speed of a car on a road

Answer 2

• speed camera
• trundle wheel
• time between two photos

Question 3

Equipment to measure the speed of a cyclist

Answer 3

• wheel sensor
• when diameter
• magnetic sensor detecting one rotation

Question 4

Typical walking speed

Answer 4

1m / s OR 2.2 mph

Question 5

Typical running speed

Answer 5

5m/s OR 11mph

Question 6

Typical cycling speed

Answer 6

7m/s or 15mph

Question 7

Typical cycling speed - in olympics

Answer 7

20m/s or 45mph

Question 8

Typical speed of strong wind

Answer 8

13m/s or 30mph

Question 9

Typical speed of a car

Answer 9

22m/s or 50mph

Question 10

Typical speed of a train

Answer 10

56m/s or 125mph

Question 11

SPEED OF SOUND

Answer 11

330m/s

Question 12

How to convert from mph to m/s

Answer 12

Question 13

Define thinking distance

Answer 13

Distance car travels whilst driver is reacting.

thinking about stopping

Question 14

Define BRAKING DISTANCE

Answer 14

Distance car travels whilst driver applies the brakes.(whilst braking force acts)

Question 15

What is stopping distance

Answer 15

STOPPING DISTANCE = THINKING + BRAKING DISTANCE DISTANCE

Question 16

Factors effecting thinking distance

Answer 16

ie. effect the DRIVER

• tiredness / energy levels
• alcohol
• drugs
• distraction

Question 17

Factors effecting braking distance

Answer 17

• weather = wet or dry roads
• worn tyres
• faulty breaks
• badly maintained roads

Question 18

Why does the braking distance of a car increase if the road is wet?

Answer 18

The distance increases because the force of friction between tyres and road decreases.

Question 19

What’s the key word when they ask you about thinking or braking distance

Answer 19

DISTANCE!!

it’s DISTANCED TRAVELLED not TIMEEEE!

Question 20

What does the area under a velocity - time graph show

Answer 20

Distance

Question 21

Why is a large negative acceleration dangerous - without a seatbelt

Answer 21

If the car slows down suddenly the belt exerts a force on you. Without it you would continue to move with your original speed, and could collide with the dashboard or the seat in front of you, causing injury to yourself or others.

Question 22

Why is a large negative acceleration dangerous - with a seatbelt

Answer 22

If your deceleration (negative acceleration) is very large the seatbelt can cause compression injuries. Also, you can injure your internal organs because they continue to move inside your body even if your ribs are stopped by the seatbelt.

Question 23

Cool textbook fun fact

Answer 23

If the acceleration that you experience is about twice the acceleration due to gravity (g = 9.81 m/s7), you feel a force equal to twice your weight, which people sometimes call ‘2g. You experience accelerations of about 5g on some rollercoasters.