topic 1 - motion

• why is it safer for drive in smooth conditions?

  • in wet and icy conditions, there is less friction between the tyres and the road surface so there would be a greater braking distance
• what are some examples of contact forces ?

  . air resistance

  . tension

  . normal force

  . friction
• what are some examples of a non-contact force?

  . gravitational force

  . magnetic force

  . electromagnetic force
• what does newtons first law state?

  a resultant force is required to change the motion of an object.

  therefore:

  if there's no resultant force on a stationary object, it remains stationary

  and

  if there is no resultant force on a moving object , it moves at a constant velocity
• What does newtons second law state?

  if an object moves in a circle, it has a constant speed

  when the speed is constant , the direction changes

  this means that the velocity is constantly changing
• what is the formula for newtons second law?

  $f =$$ma$
• what is inertia?

  the motion of an object will remain unchanged if there is no resultant force

  the inertial mass determines how difficult it is to change an objects velocity
• what does newtons third law state?


  every cation force has an equal and opposite reaction force
• what is meant by conservation of momentum?


  total momentum before collisions is equal to total momentum after collisions
• how to apply newtons second law of motion?


  if an object is moving in a circle, it has a constant speed , so when the speed is constant the direction changes which means that the velocity is constantly changing which leads so acceleration.
• what is the equation for w?

  $w=$$mgfs$
• what is centripetal force?


  a force that is directed in the centre of a circle when its id undergoing a form of motion
• what is the formula for change in momentum?


  $m=$$mv-mv/t$
• what is the difference between a vector quantity and a scalar quantity?


  a vector quantity has magnitude and direction

  a scalar quantity only has magnitude
• what are some examples of scalar and vector quantities ?

  scalar: speed, distance time

  vector: displacement, acelleration
• what is the equations of acceleration?


  v-u /t
• what is the equation distance acceleration?


  v2-u2= 2xax
• what is stopping distance?


  The distance a vehicle travels from the moment the driver applies the brakes until the vehicle comes to a complete stop.
• breaking distance?


  before reaction after seeing a hazard, there's a thinking distance and then a breaking distance after the reaction?
• what are the dangers of large deccelerations?

  when a car crashes , there is a big deceleration for a long period of time so when there is a huge force exerted there is an injury
• how do seatbelts prevent injury?

  they provide a smaller momentum before the crash. The elasticity

  of the seatbelts pull you forward and not out the car. the force is then exerted on the passenger which prevents injury
• what is the formula for momentum?


  $p=$$mv$