Mechanics Definitions 0.0 / 5 PhysicsMechanics DefinitionsA2/A-levelOCR Created by: roopaCreated on: 11-04-15 13:02 Define a scalar quantity and give an example Magnitude without direction, e.g. length, area, mass, temperature 1 of 23 Define a vector quantity and give an example Has both magnitude and direction e.g. force, momentum, acceleration 2 of 23 Define displacement Net distance moved in a particular direction 3 of 23 Define instantaneous speed Speed measured between two points a very small distance apart (dx/dt) 4 of 23 Define velocity Speed in a given direction 5 of 23 Define acceleration Change in velocity over time taken (a = dv/dt) 6 of 23 Define the Newton The net force which gives a mass of 1kg an acceleration of 1m/s^2 7 of 23 Define torque of a couple One of the forces x perpendicular distance from pivot 8 of 23 Define moment of force moment = force x perpendicular distance 9 of 23 Define thinking distance The distance travelled by the car from when the driver sees a problem and the brakes are applied 10 of 23 Define braking distance The distance travelled by the car between when the brakes are applied and the car stops. 11 of 23 Define stopping distance Thinking distance + braking distance 12 of 23 Define work done by a force force x distance moved in the direction of the force 13 of 23 Define the Joule Energy required to move a weight of 1N a distance of 1m 14 of 23 Define Power Power is the rate of work done, so work done /time 15 of 23 Define the Watt Power required to move 1N a distance of 1m in 1s 16 of 23 Define Stress Stress = force/cross sectional area 17 of 23 Define Strain Strain = extension / original length 18 of 23 Define Young's Modulus Stress/strain (gradient of the graph in the linear region) 19 of 23 Define ultimate tensile strength Maximum stress material can withstand before fracture 20 of 23 Define elastic deformation Returns to original shape when the external force is removed (so long as the elastic limit is not exceeded) 21 of 23 Define plastic deformation Material does not return to original shape. The material is permanently deformed 22 of 23 Define Density Density = mass / volume 23 of 23

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