Forces Flashcards
Effects of forces
- changes direction
- changes shape and mass
- change shape of moving object
- stop moving object
- move stationary object
Newtons 1st law
A stationary object will remain stationary and a moving object will remain in motion unless acted upon by another force
Newtons 2nd law
The amount of acceleration of a body is proportional to the acting force and inversely proportional to the mass of body
(F = ma)
Newtons 3rd law
For every action there is an equal but opposite reaction
Hookes law
The extension of the spring is directly proportional to the force applied. (given that it doesnt exceed limit of elasticity)
Limit of proportionality
When the extension of an elastic object is no longer proportional to the force applied
Types of elasticity
Compress
Pull/twist
Stretch
Inelasticity
When an object doesnt turn back into its original shape and stays deformed
Elastic
object that can return into its original shape
Formula for spring constant
F(force) = ke
K = spring constant (F/e)
E = extension (final-initial length)
Centripetal force
centre seeking force
definition: a force that acts towards the centre and keeps an object moving in a circular path.
factors affecting centripetal force
F = (mv^2)/r
mass/velocity increase, force increase
radius increase, force decrease
application of centripetal force
Round about
rounding a loop
satelite (natural communication0
derail ___ of circle
direction change so speed is ____
tangent
constant (f =ma)
What is centre of mass
-A point at which mass or weight is concentrated
- a point at which the mass or weight appear to act
Steps for drawing vector diagram
- appropriate scale
- draw vector force
- identify resultant force
- draw triangle
- measure the resultant force(length of hypothenuse)
resultant force
-summation of all forces
-net force
same direction: addition
opposite direction: subtraction
How to determine if an object will topple
Topples if - centre of mass exceeds base region
Doesnt topple if - centre of mass is within the base region
Stable equilibrium
-object tends to remain unmoved in this state
-centre of mass returns to original position
unstable equlibirum
-requires little or not force to topple over
-centre of mass is vertically displaced
neutral equlibrium
-object moves to a new position and will tend to stop as soon as energy is dissipated
- centre of mass moves to a new position and there is not vertical displacement
