ANGULAR
MOTION in TENNIS &n=
bsp;
Unit 13

Dr.
John P. Cise, Professor of Physics,

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---------------------------------------

Roddick Evens

**File=
d at
11:15 p.m. ET New York =
Times April 7,
2006**

Andy Roddi=
ck
beat Nicolas Massu in straight sets Friday to e=
ven
the United States' Davis Cup quarterfinal against Chile at 1-1.Roddick beat=
Massu 6-3, 7-6 (5), 7-6 (5) to square the best-of-five
competition in Rancho Mirage, Calif., after Chile's Fernando Gonzalez outla=
sted
James Blake 6-7 (5), 0-6, 7-=
6 (2),
6-4, 10-8 in a 4-hour, 20-minute marathon opening matc=
h.Massu
and Gonzalez, the 2004 Olympic doubles champions, are slated to team against
twins Bob and Mike Bryan in Saturday's lone match.

Roddick used his big serves -- one clocked at * 150 mph* -- to b=
eat Massu on the grass at Mission Hills Country Club, the
surface and locale chosen by the host U.S. team.

_______=
________________________________________________

Some kn=
own
variables: The tennis racket on serve moves from rest in a semicircle prior=
to
the ball being hit. The average arm is 3 feet long and the distance from ha=
nd
holding the racket to the “sweet center of racket head” is abou=
t 2
feet.

(1)&=
nbsp; Find the angular acceleration of Roddick’s racket through this semicircle of
acceleration?

(2)&=
nbsp; Find the time to reach 150 mph?

(3)&=
nbsp; Find the tangential linear acceleration the i=
nstant
the ball is hit?

(4)&=
nbsp; Find the centripetal acceleration at the time(point) the ball is hit?

(5)&=
nbsp; Find the vector resultant=
(with
angle) of the two accelerations in (3)&(4)?

(6)&=
nbsp; Find the angular velocity of racket at the ti=
me the
ball is hit?

(7)&=
nbsp; Find the angular velocity at Roddick’s
hand at time ball is hit?

(8)&=
nbsp; Find the tangential linear velocity at the po=
int
where the ball is hit?

(9)&=
nbsp; Find the linear velocity of Roddick’s
hand at time the ball is hit?