braking and momentum Flashcards
how do you calculate the stopping distance
stopping distance = thinking + braking distance
what is the thinking distance
the distance the vehicle travels during the drivers reaction time
what is the braking distance
the distance the vehicle travels once the brakes have been applied
what is the relationship between braking distance and thinking distance
thinking distance is proportional to the speed of the vehicle (straight line on graph)
what is the relationship between the braking distance and speed
braking distance is proportional to the speed squared
what are the factors that affect braking distance
speed of the vehicle
road conditions
the condition of brakes and tires
(any condition that causes less friction between the tyres and the road can lead to skidding which increases the braking distance
what affects reaction time
tiredness
alcohol
distractions
how can reaction time be calculated
computer
or ruler drop test
what is the relationship between braking force and deceleration
the greater the braking force the larger the deceleration
what may happen if the braking force is to large
the brakes may over heat or the car may skid meaning driver loses control
what is momentum
a property of all moving objects
what type of quantity is momentum
vector
what affect does the time taken for a change in momentum have on the rate and force
the greater the time taken for a change in momentum of an object
- the smaller the rate of change of momentum
- the smaller the force it experiences
what safety feature increase the time taken for the change in momentum
air bags and crumple zones in cars
cycling helmets
crash mats in gymnastics
what is the relationship between force acting on an object and rate of change of momentum
they are equal
