forces and shape Flashcards
three examples of contact forces
- friction
- air resistance
- buoyancy
three examples of non-contact forces
- magnetic
- gravity
- electrostatic
what force is always 90 degrees to the surface on a force diagram
normal contact force
what force is always vertically down on a force diagram
weight
how are the arrows drawn when an object is moving at a constant speed
the same length
what is the definition of a newton
one newton is the force due to gravity acting on a 100g mass
an example of how friction is formed
rubbing palms together. the friction is between your palms
an example of how drag is formed
forces that act against the motion of something
an example of how electrostatic force is formed
hair being attracted to a charged balloon
an example of how tension is formed
in a rope being pulled
what is are unbalanced forces
resultant or net forces that cause an abject to accelerate or decelerate
what does it mean if there is no resultant force
the object would either be stationary or moving at a constant velocity
what is hooke’s law
force and extension are directly proportional
how is Hooke’s law shown on a graph
straight line passing through the origin
what happens when the springs are overloaded
Hooke’s law cannot be applied
what is elastic limit
the limit of stretching between temporary and permanent deformation
how is elastic limit shown on a graph
graph line starts to curve
what does it mean when the spring is no longer elastic
it becomes plastic
how are wires behaved
the same way as springs
what is the behaviour of brittle objects
they tend not to stretch. they just break
how is breaking point shown on a graph
the line stops at the breaking point
how do elastic bands behave
- they behave elastically
- thy do not obey Hooke’s Law
