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Pl
l   . (7.24)
c
EF
Given the weight of the rod, but bring it to the site of
impact, the
 P  Q l
l   , (7.25)
см
EF
where  – reduction factor of the distributed mass of the rod to
the point of impact.
Dividing (7.25) by (7.24), we obtain the correction  , that should
be made to the formula (7.14)
l  Q
  см  1  , (7.26)
l  P
c
than the formula taking into account the dynamic factor of mass
of the rod takes the form

2h
k  1 1 .
д  Q  (7.27)
l  c  1  
 P 
Now find an expression for determining the reduction
factor  .
The kinetic energy T of the elastic system immediately
after impact is calculated by the formula

 2
T   x dQ ,
Q 2g

 2
where x dQ – kinetic energy of an elementary particle of
2g
weight dQ , that moves with the speed after impact  ..
x
The magnitude of the concentrated mass  Q / g taken
Q 2
such that its kinetic energy  is equal T , i.e.
2g

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