CHAPTER 4 Flashcards
FORCE
push or pull on an object, measured in N
WEIGHT
the gravitational force on an object, measured in newtons, N
CENTRE OF GRAVITY
an imaginary point at which the entire weight of an object appears to act
CENTRE OF MASS
a point through which any externally applied force produces straight line motion but no rotation
PLUMB- LINE
a string with a weight used to provide a vertical reference line
FREE- BODY DIAGRAM
a diagram that represents the forces acting on a single object
NORMAL CONTACT FORCE
the force exerted by a surface on an object, which acts perpendiculary to the surface
DRAG FORCE
the resistive force exerted by a fluid on an object moving through it
AIR RESISTANCE
the drag or resistive force experienced by objects moving through air
TERMINAL VELOCITY
the content speed reached by an object when the drag force is equal and opposite to the weight of the object
MOMENT
the product of force and perpendicular distance from a pivot or stated point
PIVIOT
a point at which a body can rotate
EQUILIBRIUM
a body is in equilibrium when the net force acting on it are zero
PRINCIPLE OF MOMENTS
for a body in rotational equilibrium, the sum of the anticlockwise moments about a point is equal to the sum of the clockwise moments about the same point
TORQUE
the product of one of the forces of a couple and the perpendicular distance between the forces
