because it is important to know where exactly is the ball going to go after the
experiment. To derive the necessary theoretical relations we shall consider two bodies
having masses m1 and m2, respectively [22]. The speeds of the bodies before the
strike are v1 and v2 and after the collision, u1 and u2, respectively. Applying the
theorem for the preservation of the amount of movement of a mechanical system we
obtain the following expression:
This expression is projected on the tangent and normal lines drawn at the point
of contact between the bodies and the following two expressions result form this:
To be able to determine the unknown values we shall have to add to the above
expressions the relations expressing the two Newton impact laws:
From the second and fourth expression we obtain:
and from the first and the third one: u1n and u2n
Loading the tennis racket
7.3.1 Tennis racket simulation
The tennis racket generally
comprises a head, representing a mesh frame (rim),
and a body made in the shape of
a handle. The tennis racket configuration is very
ific and complicated. This results in many difficulties when calculating the load
and size of the racket using conventional methods. Therefore, it is more convenient for
the purposes of a preliminary study to build a simplified model of the racket.
We can successfully use a surface loaded beam fixed in one of its ends for the
purpose. We assume the beam has constant round, rectangular or squar
-sectional area. To establish the extent of adequacy of the suggested simulation
model we decided to make the following experimental set-up [23]:
The tennis racket is fixed static at its handle using a vice. Then using a balance,
