forces and motion

• contact force


  when objects physically touching e.g. normal reaction force, friction and air resistance
• non- contact force

  when not touching e.g. magnetism, electrostatic force and gravity
• a vector

  a quantity that has magnitude &direction
• a scalar vector 


  a quantity that only has magnitude
• how can the resultant force be found 


  by adding them if at right angles, make a triangle and use pythagoras
• weight equation 


  mass x gravitational field strength
• what happens when you hold an object

  you must be pushing upwards with a force that's the same size as its weight
• work done


  energy transferred by a force
• work done equation


  force x distance
• springs


  any object that deforms elastically obeys hooves law (force and extent are directly proportional)
• equation for force spring


  spring constant x extension
• the gradient of a distance graph gives you


  speed/velocity
• the gradient of a velocity time graph gives you


  the acceleration
• newtons 1st law 


  if no resultant force acts on an object it's motion will be constant (velocity will not change)
• newtons 2nd law


  mass x acceleration
• newtons 3rd law


  for every action (force), there is equal and opposite (force) (this is not balanced forces.)
• stopping distance =


  thinking distance + braking distance
• what happens when you double you speed


  you double your thinking distance
• thinking distance is affected by


  • speed
  • alchol
  • drugs
• braking distance is affected by


  • weather conditions
  • condition of brakes, tyres & road
• momentum


  mass x velocity
• in any collision is total momentum always conserved


  yes
• if an object moves 3 meters to the left and then 3 meters back to its initial position, what is the objects total displacement

  • the objects has zero displacement
  • object starts and ends at the same point
  • displacement is a vector quantity so it also involves direction
• state a typical value for speed of sound


  330 m/s
• what is a typical value for human walking speed


  1.5m/s
• what is a typical value for human running speed


  3 m/s
• what is a typical value for human cycling speed


  6 m/ s
• weight


  mass x gravitational field strength