P4 pt4 Flashcards
What is Newtons first law?
If a resultant force is 0, then the object is either stationary or moves at a constant speed in the same direction
What is Newtons second law?
The acceleration of an object is proportional to the resultant force of an object and inversely proportional to the mass of an object (force= mass x acceleration)
What is Newtons third law?
When 2 objects interact, the forces they exert on each other are equal and opposite
What is the stopping distance of a vehicle?
It is the sum of the distance that the vehicle travels during the drivers reaction time (thinking distance) and the distance it travels under the braking force (braking distance). Stopping distance = thinking distance + braking distance
What is a typical reaction time for a person?
0.2s to 0.9s
What can affect a drivers reaction time?
Tiredness, drugs and alcohol
What can affect the braking distance?
Adverse road/weather conditions(wet/icy roads) and poor condition of the vehicle (worn out tyres/brakes)
What happens when a force is applied to the brakes of a vehicle?
Work done by the friction force between the brakes and the wheel reduces the kinetic energy of the vehicle and the temperature of the brakes increases
What happens if the braking force is larger?
The larger the braking force, the greater the deacceleration of the vehicle. Large deaccelerations may lead to brakes overheating/loss of control
What is the equation for momentum?
MPV Momentum=mass x velocity
What is the conservation of momentum?
In a closed system, the total momentum before an event is equal to the total momentum after an event
