Physics P4 Double award Physics module 4 0.0 / 5 ? SciencePhysicsGCSEOCR Created by: NicoleCaitlinCreated on: 23-12-14 12:05 P4 Units mph (imperial) km/hr (metric) decimal hours - 30 mins = 0.5 hours Speed Equation speed = distance travelled / time taken m/s = m / s Average Speed - if you have a long journey, the final distance and time will give you an average speed Instantaneous Speed - the speed you are doing in that instant 1 of 7 P4.2 Displacement - the distance between the starting point and object in a particular direction (not distance journied) Distance-Time graphs steeper the line - faster Velocity - speed with a direction Accelerates - speeding up Decelerates - slowing down Average acceleration equation average acceleration = change in speed / time taken for change 2 of 7 P4.2 Speed - time graph upward slope - accelerating downward slope - decelerating straight line (not on/near to horizontal) - constant speed straight line (near to horizontal) - slow straight line (on horizontal) - stationary 3 of 7 P4 - Forces 7 types gravity friction air resistance magnetic normal reaction upthrust lift measured in Newtons (N) Newtons third law of Motion when two objects interact, each experiences a force. The two forces are equal in size but opposite in direction. 4 of 7 P4 - Forces/Energy Interaction pairs of forces one force acts on one object, one force acts on the other opposite directions forces are equal in size Energy Energy is measured in Joules, J 9 types kinetic sound nuclear elastic light electrical heat chemical gravitational potential 5 of 7 P4 - Energy Kinetic energy equation KE = 1/2 mass x velocity^2 J = 1/2 kg x m/s^2 Gravitational potential equation 100g = 1N GPE = weight x height 1 kg = 10N J = N x m Work equation Work = force x distance J = N x m 6 of 7 P4 - Other equations Momentum momentum = mass x velocity kgm/s = kg x m/s Change in Momentum change in momentum = force x time kgm/s or Ns = N x s 7 of 7

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