Physics

Physics

vectors and velocity
1. some quantities are vectors and include size as well as direction
2. speed=distance/time
3. distance time graphs
  1. a small steady incline means something is accelerating
  2. a steep line upwards means it something is travelling at speed
  3. a horizontal line means something is stationary
velocity and acceleration
1. acceleration is a change in velocity
2. slowing down is also an acceleration
3. acceleration=change in velocity(m/s) / time taken(s)
  1. a=(v-u) / t
    1. a=acceleration v=final velocity u=initial velocity t=time taken
4. a velocity time graph shows how the velocity of an object changes with time. The distance can be calculated from the area under the line
5. a sloping line means the object is accelerating, a straight line means the object is moving at a constant velocity, a line going downwards means the object is slowing down, the highest point is the objects final velocity
resultant forces
1. if there is more than one force on a object all the forces can be combined into a resultant force
2. a force is a vector quantity, because it has a direction as well as a size
3. a free body diagram represents the forces acting on an object
  1. the arrows represent the size of the force
4. action and reaction forces need 2 objects
  1. e.g kicking a ball
    1. the force from the foot on the ball is the action force.
    2. the ball exerts and equal opposite reaction force on the foot
5. measured in newtons (N)
forces and acceleration
1. newtons second law
  1. if the forces on an object are unbalanced 2 things about an object can change. Its speed or direction
2. force =mass x acceleration
  1. f=ma
3. the greater the force,the greater the acceleration for a constant mass
4. the greater the mass , the smaller the acceleration for a constant force
5. 1kg=1000g
6. accelertion =m/s*2
7. mass=kg
terminal velocity
1. weight =mass x gravitational field strength
  1. (N)=newtons
  2. (KG)=kilograms
  3. (N/KG) or (m/s*2)
2. earth =9.8 n/kg moon=1.6 n/kg jupiter=25.4 n/kg
3. mass=the amount of matter in an object
4. weight=the force of gravity on an object

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	Erstellt von Martha Edney vor fast 11 Jahre