
328 Classical Mechanics
© 2010 Taylor & Francis Group, LLC
in which θ
l
= 30°. Solving for
′
p
1
and
′
p
, we find
′
==
′
pp pp
11 12
30 32 30
cos/ si
and
.
Thus, the kinetic energies after impact are
′
=
′
===T
p
m
p
m
T
1
1
2
1
1
2
1
2
3
8
3
4
3MeV
and
′
=
′
===T
p
m
p
m
T
2
2
2
2
1
2
1
244
1MeV
.
10.4 NUCLEAR SIZES
The Rutherford alpha particle scattering experiment provided the rst evidence that nuclei are of
nite size, much smaller than the atomic dimensions. In this α particle scattering experiment, the
distance of closest approach is found from Equation 10.23 to be
r
min
=
α
(10.41)
where
α = ℓ
2
/mk
and
ε= +
1
2
2
2
E
mk
/
.
From the last two expressions, we obtain
k