Sports Equipment Final

The most common midsole foam is:

ethylene vinyl acetate

Which foaming technique can result in trace contaminants left behind in the foam

chemical foaming

the curve below shows deformation of a midsole foam during loading and unloading. the pink area between the lines represents

energy loss

ethylene vinyl acetate is a:

copolymer

cross linking of EVA midsole foam will make the polymer:

harder

polyurethane is commonly formed by reacting __

a polyol with an isocyanate

what is the order of typical energy return in midsole foams

EVA<TPU<PEBAX

the common structural aspect of all superfoams is:

a polymer with alternating hard and soft segments

A foam made by a supercritical foaming process can result in improved energy return and more stable performance

True

A large moment of inertia will ______________

reduce twisting of the driver head

The highest performing shoes have energy return values on the order of ___________.

80-90%

The coefficient of restitution of a driver ___

describes a measurement of how efficiently a golf club’s face transfers energy to the ball when it strikes

the densest (least porosity) microstructure of a driver will result from:

forging

the strongest parts of a driver can be expected to result from:

forging

which of the following is true about sintering

the reason sintering occurs (i.e. the driving force) is to reduce the surface energy by particle coalescence

grooves in irons are intended to _

impart back spin to the golf ball

sheet wound composite shafts __

will have a “spine” that will affect behavior

the face of a driver is bulged (not flat) __

to straighten the trajectory of an off-center ball strike

dimples can vary in diameter and depth. deep dimples generate _ than (as) shallow dimples

less spin

a higher spinning golf ball will experience _ than (as) a slower spinning golf ball

more lift

smaller diameter dimples generally give the ball _ and better control in the wind

a lower trajectory

larger diameter dimples give the ball a _ flight time

longer

the most common golf ball core material is

polybutadiene

surlyn, a common golf ball cover material is an example of a(n) _

ionomer

dimples on a golf ball create __

more turbulence at the ball surface

in a three piece golf ball where each layer has a different density, if a layer is non-concentric it will affect the _ of the ball

center of gravity

knots in wood decrease strength because

they increase the fraction of off axis cellulose fibers

which is true about bat hoop mode frequency

higher performing bats tend to have lower hoop mode frequencies

which of the following is true

ash bats are more prone to single piece failures than maple bats

the size of a tennis racket “sweet spot can be increased by __”

increasing the frame stiffness

the maximum coefficient of restitution in a tennis racket is __

near the throat of the racket

the dead spot (with minimal energy return) is located __

near the tip of the racket

composite tennis racket frames are __

hollow

some tennis strings are multifilamentary. the flexibility and elasticity of the string depends on the angle at which the filaments are wound. a tighter wind yields __

more flexible and elastic string

tennis strings undergo viscoelastic creep __

regardless of their use level

incorporation of piezoelectrics in tennis rackets for vibration control is an example of __

active damping

countervail carbon fiber composite incorporating viscoelastic material is an example of

passive damping