P8.1 Flashcards
Different ways to measure distance
measuring tape
trundle wheel
Different ways to measure time
Magnetic sensors detecting one rotation
Electronic timer
Time between two pulses
Time between two photos
Pressure sensor to start and bread laser beam to end
Formula to calculate speed
Speed = distance/time
What is the typical speed of walking, running, cycling and a car in that order
1 m/s, 5 m/s, 7 m/s, 22 m/s
What is the formula for acceleration
Acceleration = change in speed/time
What is reaction time
The time it takes for the light to reflect and hit your retina and then travel from your brain to the muscles controlling the action is reaction time.
What is the typical human reaction time
0.2 seconds
What is the thinking distance
The distance that the car travels in the reaction time of the driver.
What is braking distance
The distance the car travels before stopping when the brakes are applied after the reaction time has passed.
Factors that affect thinking distance because they affect reaction time
Drinking alcohol
Using drugs as well as some medicines
Being tired
Factors that affect the time it takes for a driver to react
Distractions (such as other people in the car)
Eating or drinking
Using a radio or satellite navigation system
What is stopping distance
The total distance that the car travels from the moment the driver sees the object until the car is stationary.
Equation for stopping distance
Stopping distance = thinking distance + braking distance
Factors affecting breaking distance
The brakes
The surface that is being driven on
The speed of the driver
What do seatbelts do in a car to protect you
The seatbelts exert a force on you. Without it you would continue going at the same speed and collide with the dashboard and seat in front of you causing injuries.
