Does Altitude Affect
the Height of the Bounce of a Golf Ball?
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"The subject of elasticity deals with the behavior of
those substances which have the property of recovering their size and
shape when the forces producing deformations are removed. We find
this elastic property to some extent in all solid bodies. When you
push a material it gives- the material is deformed. If the force is
small enough, the relative displacements of the various points in the
material are proportional to the force- we say the behavior is
elastic." (Holton).
"The elasticity attribute defines the elasticity value
of an object. The elasticity value is a floating point number between
0 and 10. A value of 0 indicates no elasticity (i.e. a brick). A
value of 10 indicates perfect elasticity (i.e. a perfect rubber
ball). The elasticity of an object determines its response when
dropped through gravity onto the gravity base or a gravity surface.
An object having an elasticity value of 0 will not bounce at all and
will remain stationary upon landing after being dropped. An object
with perfect elasticity of 10 will continue to bounce indefinitely
back to the place from which it was dropped. A value between 0 and 10
will cause a gradual degradation (relative to the value) of energy
each time the object collides with a surface."
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"In 1666, two hardwoods balls of equal size were
released from rest at a certain height. It swung down and struck the
other, which was hanging at rest. After impact, the ball stopped at
the point of impact while the second ball swung from this point to
the same height as that from which the first ball had been released.
Our law of momentum conservation explains what is
observed.
The scalar quantity
1/2mv(squared) has come to be called kinetic energy. The law of
conservation of kinetic energy , then, is not as general as the law
of conservation of momentum. If two bodies collide, the kinetic
energy may or may not be conserved, depending on the type of
collision. It is conserved if the colliding bodies do not crumple of
smash or dent or stick together or heat up or change physically in
some other way. We call any bodies that rebound without any such
change perfectly elastic. We describe collisions between them as
perfectly elastic collisions. In perfectly elastic collisions, both
momentum and kinetic energy are conserved.
Most collisions that we witness,
are not perfectly elastic and kinetic energy is not conserved. Thus,
the sum of the 1/2mv(squared)'s after the collision is less than
before the collision. Depending on how much kinetic energy is lost,
such collisions might be called partially elastic or perfectly
inelastic. The loss of kinetic energy is greatest in perfectly
inelastic collisions, when the colliding bodies remain
together.
Collisions between steel
ball-bearings, glass marbles, hardwood balls, billiard balls, or some
rubber balls(silicone rubber) are almost perfectly elastic, if the
colliding bodies are not damaged in the collision. The total kinetic
energy after the collision might be as much as, say, 96% of this
value before the collision. Examples of true perfectly elastic
collisions are found only in collisions between atoms or sub-atomic
particles."(Holton).
"Elasticity number is proportional to { (elastic
force) / (inertial force) } and is used in momentum transfer in
general and viscoelastic flow calculations in particular. It is
normally defined in the following form, where :
r = Pipe/conduit
radius
mu = Viscosity
rho =Density
theta = relaxation
Pipe/conduit radius
Viscosity
Density
relaxation time"
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