Bukhovtsev-et-al-Problems-in-Elementary-Physics

HEAT. MOLECULAR PHYSICS 291
F
On upper nut
Fpllf----.-,
o
O=Fg
On lower nut
8 Fig. 408
Hence
F _2AE cEs «(Xc-as) t
- 2E s+Ec
mvl
382. When the ring rotates, the tension T = 2- appears In It (see Probnr
tern 201). For a thin ring m=2nrAp, where A is the cross section of the
ring. Therefore. ~ =pv·.
Hence. the maximum
velocity v= V~Q!;~l m/s.
:$83. Initially, an elastic force Po acts on each nut from the side of the
extended bolt. .
The load G~ F0 cannot increase the length of the part of the bolt between
the nuts and change its tension. For this reason the force acting on the
upper nut from the side of the block will not change as long as G~ Fe-
The lower nut is acted upon by the force F0 from the side of the top part
of the bolt and by the force G from the bottom part. Since the nut is in
equilibrium, the force exerted on it from the block is F=Fo-G. Thus the
action of the load G~ F0 consists only in reducing the pressure of the lower
nut on the block.
When G > F OI the length of the bolt will increase and the force acting
on the lower nut from the side of the block will disappear. The upper nut
will be acted on by the force G.
The relation between the forces acting on the nuts and the weight of the
load G is shown in Fig. 408. .
2·7. Properties of Vapours
384. The calorimeter will contain 142 g of water and 108 g of vapour at
a temperature 100 0 C.
385. By itself, water vapour cr steam is invisible. We can observe only
a small cloud of the finest drops appearing after condensation. When the gas
burner is switched off, the streams of heated air that previously enveloped
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