Mechanics Definitions

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

Card 2

Front

Has both magnitude and direction e.g. force, momentum, acceleration

Back

Define a vector quantity and give an example

Card 3

Front

Net distance moved in a particular direction

Card 4

Front

Speed measured between two points a very small distance apart (dx/dt)

Card 5

Front

Speed in a given direction