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• Contact forces


  When the object is physically touching, such as friction or pushing something
• Non-contact forces


  Where it is not physically touching, such as gravity or a magnetic field
• Scalar


  Only has a magnitude, such as a distance or mass
• Vector


  Has a magnitude and a direction such as displacement
• Resultant force


  Found out by adding the vectors, may have to draw a triangle and use Pythagoras if they are in opposite direction. A resultant force of 0 is not accelerating
• Weight


  The mass X gravitational field strength. Weight is a force, so it is measured in newtons
• Lifting at a constant speed


  You must be doing the same force as the weight to hold it up
• Work done


  The force X distance. This is the energy transferred by a force, the force can be the weight
• Springs


  Something that elastically returns to its position and obeys hooks law until a certain point. Force and extension are directly proportional
• Hooke's law


  Force = springs constant X extension. Works for any elastic object. Is true for objects being compressed as well
• Hooke's law practical


  Have a ruler a spring and various masses. Add masses to the spring and measure how much its extension is. Put it on a graph and it proves their directionally proportional
• Elastic potential energy


  This is energy stored in the spring, it is released when the force is stopped on the spring
• Moment


  A turning force, such as with a spanner. Moment = force X distance to the pivot. We can use these for levers, to reduce the force needed to create a moment
• Gears


  A small gear needs a small amount of energy, but it can turn a large gear, creating a larger moment
• Pressure


  This is how concentrated a force is, force/are. The unit is N/M'2 or pascals
• Pressure in liquids


  Deeper you go the higher the pressure, pressure for liquids = Gravitational field strength X density X depth
• Pressure in a gas

  Due to particles colliding with the walls of a container, exerting a force. Decreasing volume, adding more gas and increasing temperature all increase the pressure due to more collisions
• Higher altitude


  Less dense higher up, there is less gas pressure there as there are less gas particles
• Speed or velocity


  Can be found through a distance time graph by finding the gradient of a tangent
• Acceleration


  This can be found by a velocity time graph, the gradient gives the acceleration, in M/S'2. This graph can go into negative values, shows how it turns around
• Displacement


  Can be found from a velocity time graph as it is the area underneath the graphs
• Newton's 1st law


  If no resultant force acts on an object, its motion will be constant, and its velocity will not change
• Newton's 2nd law


  In unbalanced forces, force = mass x acceleration
• The second law practical

  Accelerate a trolley on a track being pulled by a weight of masses hanging on a string over the other side. Use light gates to measure the acceleration between 2 points. Draw a graph of force against acceleration and should be directly proportional
• Newton's 3rd law


  Every action of force, there is an equal and opposite reaction force. Two ice skaters will push each other because of this
• Inertia


  How hard it is to stop an object in motion
• Stopping distance


  The thinking distance + braking distance. This is a measure of how far it takes the car until it completely stops. It is longer if the car is at a higher force or momentum
• Thinking distance


  How long it takes the person to press the breaks, it is affected by drugs and distraction. Doubling speed doubles, the thinking distance
• Braking distance


  How far the car goes when the person has pressed the brakes. Conditions of the car and the roads affect this. Doubling the speed quadruples the braking distance as the car loses all the kinetic energy
• Momentum


  The faster you go the more momentum you have. It is a measure of how hard it is to stop something. Momentum = mass X velocity. It is measured in KGm/s and is a vector meaning negative momentum is possible
• Total momentum


  This is always conserved in a collision, work out total collision before the event, this is the collision after the event
• Force and momentum


  Force = change in momentum/ time. Force is the rate of change in momentum. The longer the time for momentum to be lost, the lower the force
• Safety in cars


  We use seat belts, crumple zones and airbags to increase the time, so a smaller force is felt
• Waves


  Transfer energy without transferring matter, they vibrate this energy
• Longitudinal waves


  The direction of oscillation is parallel to the direction of energy transfer; it has compression and rarefactions. These are sound waves and seismic waves
• Transverse waves


  These oscillate perpendicular to the direction of energy, such as water waves and seismic S waves. These go up and down
• Waveform


  Way of representing all waves, it is the graph with the lines going up and down it. Displacement is the Y axis and X axis the distance or time. The peak of the wave is the amplitude, one complete wave gives the wavelength of time. Frequency is how many waves pass every second
• Frequency


  It is the waves per second, it can be worked by buy 1/time period
• Ripple tank


  Tells us what frequency is made, measure the distance between ten peaks and divide by 10 to get the wavelength, use the wave equation to find out wave speed
• Speed of sound waves

  A microphone to an oscilloscope, clap once next to the microphone and allow it Echoe of a wall