# Shared Flashcard Set

## Details

Unit 1 : Mechanics
for those who've got that big exam coming up OCR accredited (from http://alevel-physics.blogspot.co.uk/2009/12/list-of-definitions-for-as-mechanics-in.html)
23
Physics
Not Applicable
02/24/2014

Term
 Scalar
Definition
 A scalar is a physical property with magnitude but not direction. Another word formagnitude is size. Examples ofscalars includespeed, distance, temperature andwavelength
Term
 Vector
Definition
 This is a quantity that has both size and direction. Another word we can use for size is calledmagnitude. Examples are velocity, force, acceleration and electric current.
Term
 Displacement
Definition
 This is the distance travelled in a particular direction. The unit for distance is the metre.
Term
 Instantaneous Speed
Definition
 Thisisthe speed of an object at amoment in time. Acars speedometer gives the driver aninstantaneous speed.
Term
 Average Speed
Definition
 A measure of the total distance travelled in a unit time.
Term
 Velocity
Definition
 The velocity of a moving objectis its displacement per unit time
Term
 Acceleration
Definition
 The acceleration of an object is its rate of change of velocity
Term
 The Newton
Definition
 The Newton is the unit of force. 1 N is the force which gives a mass of 1 Kg an accelerationof 1 ms^-2
Term
 The Torque of a Couple
Definition
 This is the turning effect due to a couple. It is measured in Newton metres (Nm).
Term
 Themoment of a Force
Definition
 Themoment of a force is theturning effect due to a single force.It is calculated bymultiplying the force by the perpendicular distance from a given point. The units areNewtonmetres. (Nm)
Term
 Thinking Distance
Definition
 This is the distance travelledby a vehiclefrom seeing the need to stop to applying thebrakes
Term
 Braking Distance
Definition
 The distance a vehicle travels while decelerating to a stop. This is the distance travelledafter the brakes have been applied.
Term
 Stopping Distance
Definition
 The stopping distance is the thinking distance added to the braking distance.
Term
 Work Done
Definition
 The product (multipliedtogether)ofaForce and the distance moved in the direction of theforcegives the work doneby the force. It can also be thought of as the energy convertedfrom one form into another. The units for work done are Joules. (J)
Term
 The Joule
Definition
 This is the unit of energy. 1 Joule is the work done when a force of 1 N moves its point ofapplication 1 m in the direction of the force.
Term
 Power
Definition
 Power it the rate at which work is done. It is measured in Watts (W).
Term
 The Watt
Definition
 This is the unit of power. One watt is equalto one joule per second. 1 W = 1JS^-1
Term
 Stress
Definition
 This is the force per unit cross-sectional area. It is measured in Nm-2or Pascals (Pa).
Term
 Strain
Definition
 This is the extension per unitlength.It has no units
Term
 Young Modulus
Definition
 This is the ratio between stress and strain i.e. the stress divided by the strain. It has thesame units as stress namelyNewtonmetres squared(Nm-2)orPascal(Pa)
Term
 Ultimate Tensile Stress
Definition
 This is themaximum tensile(stretching)force that can be applied to an object before itbreaks
Term
 Elastic Deformation
Definition
 This means thatthe object will return to its original shape when the deforming force isremoved.
Term
 Plastic Deformation
Definition
 This means that the object will not return to its originalshape when the deforming force isremoved,it becomes permanently deformed
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