Forces Flashcards
Def non contact force
A force that act through space in fields over a distance
Def a lubricant
Is a substance that reduces friction between two moving surfaces
Name the effects of a force
Chang position of rest of an object
Change speed or direction of a moving object
Cause rotation
Change in shape
State Newtons third law
The mutual similar forces of action and reaction
between 2 bodies
are equal, opposite and collinear
State Hooks Law
States that the extension of a spiral spring is directly proportional to the stretching force
provided that the spring is not stretched beyond its elastic limit
Give the mathematical expression of Hooks Law
F = ke
Def elastic deformation
It is the temporary change in shape of an object which is reversed when the force is removed so that the object returns to its original shape
Def limit of proportionality
It is the point beyond which the spring no longer obeys Hooks Law
Def strain energy
Is the ability of an object to perform work as a result of a change in shape
Def Rotation
Is the effect of a Force
When it is applied to a body
Which is free to move around a point
Def fulcrum
The point about which rotation occurs
Def a Moment
Product of the force and the perpendicular distance
Of the line of action of the force
From the pivot
State the law of Moments
For a lever in equilibrium,
the sum of the clockwise moments
Equals
The sum of the anticlockwise moments
Def the centre of gravity.
also centre of Mass
It is the point
At which
The whole weight of the body
Can be considered to act
Name 2 ways to increas stability of a body
1) . Lower the centre of mass
2) . Broaden the base of the object
Define a lever
It is a device
that can turn about a pivot
Name the class of lever utilized in a see saw
1st class
Name the class of lever utilized in a nut cracker
2nd Class
Name the class of lever utilized in a wheelbarrow
2nd Class Lever
Name the class of lever utilized in braaivleis tongs
3rd Class Lever
State the Triangle Law
When 3 forces are in equilibrium
they can be represented in both magnitude and direction
by the 3 sides of a triangle
Taken in order
Define a Newton
It is the force which gives a mass of 1kg an acceleration of 1m/s
State Newtons 2nd law
When a resultant force is applied to a body
it produces an accelerationin the direction of the force
That is directly proportional to the force
and inversely proportional to the mass of the object
Define a contact force
Is a force that is extended directly on an object
