p8.1

Question 1

give examples of devises used to measure speeds

Answer 1

electronic timing - using lasers. this times how long it takes for a thing to pass an the two lasers.
wheel sensor - used by cyclist
speed cameras - compare time between photos
speed gun

Question 2

what is reaction time and how do we measure it

Answer 2

reaction time = time taken for the subject to react to an external stimulus.
one way to measure reaction time is the ruler drop test.
reaction time is about 0.2 seconds

Question 3

what is thinking distance

Answer 3

this is the distance travelled before a response is initiated.
eg if you are on a bike and you break suddenly you have travelled a distance before you begin to break. this is thinking distance

Question 4

what factors effect thinking distance

Answer 4

• alcohol
• drugs
• being tired
• getting older

Question 5

what factors increase thinking distance in a car

Answer 5

• distractions from others in the car
• eating or drinking
• satellites or other navigation systems

Question 6

what is braking distance

Answer 6

when the signal to brake has caused the body to push down on the brake the vehicle travels a distance before it stops. the braking distance depends on the brakes, surface and speed. not the driver

Question 7

what is stopping distance

Answer 7

this is the total distance the driver travels before the vehicle has stopped. thinking distance + braking distance

Question 8

why is abrupt decelerations dangerous

Answer 8

fast deceleration can cause injury to your internal organs as they continue to move even after your ribs have been stopped by a seat belt

Question 9

why are cars designed to crumple in a car crash

Answer 9

by doing this the distance that the person travels before they stop is increased therefor the force they feel is decreased