In fall 2006, the National Basketball Association (NBA)
started using baskctballs rnadc with synthetic, or man-made, material instead of
leather. They made the change because they wanted every basketball they use to
feel and bounce the same. Not all leather balls are exactly alike in weight or
how they bounce, but the synthetic balls are. However, some
players complained right away that the new balls bounced differently ancl were
actually harder to control than the leather ones. Physics
helped answer questions about why the new balls felt different. For example, the
scientists studied friction, which in this case affects the ability of a player
to hold onto a ball. "The greater the friction, the better it will stick to his
hand." explains a scientist. Tests on both wet and dry balls
showed that while the synthetic ball was easier to hold onto when dry, it had
less friction and became much harder to hold onto when wet. That’s because sweat
stays on the surface of the synthetic balls but gets taken into the leather
balls. The scientists also testecl bounce ancl found that the
logo printed on the new balls made their surface uneven and caused them to
bounce a little strangely compared with the leather balls. In
January, the NBA went back to using the leaLher balls. They aren’t
perfect, but for now, that’s just the way the ball bounces. Why were the synthetic balls expected to be used in NBA according to
the text
A.Because they are easier to control.
B.Because they waste less material.
C.Because Lhey look exactly dlike.
D.Because they feel and bounce alike.