6 forces in equilibrium Flashcards
conditions for equilibrium
resultant forces =0
(three forces = trinagle)
the principle of moments
tilting
if the object topples then the lie of action would be outside the base
the tall = centre of mass is high and the base is narrow
unstable equilibrium
if it is displaced from equilibrium it will not return. the centre of mass of the plank is directly above the supporting force
stable equilibrium
displace then released and it returns to original postion
couples
a pair of equal and opposite coplanar forces acting on a body but not on the same line
the centre of mass
a body is a point through which a single force on a body has no turning effect
force
acceleration
weight
vector qualities
displacement
velocity
force
distance from a given direction
speed in a given direction
scalar
any physical quality that is not directions;
vector
a physical quanity that has direction as well as a magnitude
displacement
distance in a given direction
velocity
speed in a given direction
stage 1 from O to A (vector OA)
stage 2 from A to B (vector AB)
OB = OA + AB
resultant vector
in general if the two perpendicular forces are F1 and F2
magnitude of resultant F= (F1 + F2)^2
angle between the resultant and F1 is given by tan = F2/F1
moment of the force
force X perpendicular distance from the point to the line of action of the force
