2.2 Mechanics Flashcards
What is newtons first law
Body will remain at rest or continue to move unless acted upon by a force
What is force
vector quantity
has magnitude and direction
What is moment
Turning effect produced by a force acting at a distance
What is opposing moments
Total moments that act against each other and are applied at points separated by a distance
What is a couple
Pair of forces that are equal in magnitude and opposite in direction
What is scalar quantities
Have magnitude but no direction
What is vector quantities
Have both magnitude and direction
What is Centre Of Gravity
Imaginary point where all weight of object is said to act
Five basic structural stresses
Tension
Compression
Shear
Bending
Torsion
What is strain
Deformation of material due to stress
What is elasticity
Ability of material to return to its original shape after external force has been removed
What is tension
Stress being applied which tends to increase the length of body
What is hooke’s law
Extension of an elastic object is directly proportional to the force applied to it
Young’s Modulus
Stress/Strain
What is compression
Force applied which tends to shorten or squeeze a body
What is shear
Tries to slice a bod apart by sliding one later over another
What is torsion
When material is twisted
Combination of tension and compression
What is hardness
Tendency to resist indentation
What is strength
Withstand applied force without failure
What is toughness
Tendency to resist breakage when deforming or when impact forces are applied
What is brittleness
Tendency to break without change of shape
What is elasticity
Return to original shape when external force is removed
What is Malleability
Tendency to undergo compressive stress without damage
What is ductility
Tendency to undergo tensile stress without damage
What is inert
Substance that will not chemically combine with another substance
What is atmospheric pressure
Force exerted by weight of the atmosphere
Average atmospheric pressure at sea level
14.7 PSI
What is absolute pressure
Pressure of having nothing inside a space (perfect vacuum)