# Physics AS definitions

 .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } Acceleration Change in velocity divided by time taken Speed Distance travelled divided by time taken Velocity Displacement divided by time taken Displacement The straight line distance from a reference point in a single specified direction Vector Quantities that have both magintude and direction Scalar Quantities that are fully defined by by magnitude only Equilibrium No resultant forceNo resultant moment Moment Force multiplied by the perpendicular distance from the line of action of the force to the pivot Principle of moments Sum of clockwise moments is equal to sum of anti-clockwise moments when the object is in equilibrium about the same pivot Centre of gravity The single point where the entire weight of a body appears to act Couple A pair of equal and opposite forces whose lines of action do not coincide Torque of a couple One of the forces multiplied by the perpendicular distance between the forces Density Mass divided by volume Pressure Force divided by area Spring constant Force divided by extension Hooke's Law Extension is directly proportional to force provided the elastic limit has not been exceeded Stress Force divided by cross-sectional area Strain Extension divided by original length Young's Modulus Tensile stress divided tensile strain Ductile material Can be easily and permenantly stretched into thin wires Elastic Materials return to their original shape and size when the applied force is removed Elastic limit The maximum load up to which the material can regain its original shape and size when the load is removed Plastic Material does not return to its original shape and size when the load is removed Weight The force of gravity on the mass of a body Joule The work done when a force of 1N moves its point of application by 1m in the direction of the force Kinetic energy The energy of a body due to movement Newton The force needed to give an acceleration of 1ms-2 to a mass of 1kg Graviational potential energy The energy a body has due to its position Power Work done divided by time Work Force multiplied by distance moved in the direction of the force Braking distance Distance travelled from when the brakes are applied until the car comes to a stop Thinking distance Distance travelled during the drivers reaction time before the brakes are applied=speed x reaction time Stopping distance Thinking distance + braking distance UTS The maximum stress a material can withstand before fracture Strain energy (3 methods) Area under F-x graph Thinking distance = speed x reaction time Gradient of displacement-time graph velocity Gradient of a velocity-time graph acceleration Area under a velocity-time graph displacement .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } Authorjpopat ID190684 Card SetPhysics AS definitions DescriptionPhysics AS definitions Updated2013-04-14T19:57:34Z Show Answers