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

MECHANICS
61
Fig. lUI
263. A cup and a V-shaped mercury barometers are brought
into equilibrium on a very sensitive balance (Fig. 107). The
barometers are made of the same material, have tubes of the
same diameter and contain the same amount of mercury. The
distance between the soldered ends of the tubes and the upper
levels of the mercury in them is also the same. How will the
equilibrium of the balance change if the atmospheric pressure
grows?
264. Appraise the weight of the Earth's atmosphere.
265. An air mattress is filled with air to a certain pressure
exceeding the atmospheric pressure. When will the air pressure
in the mattress be greater: when a man stands on it or when
he lies on it?
266. A wheel of a motor vehicle is designed as follows.
A rubber tube enclosed in a tyre casing is placed onto a metallic
rim. The tube is then inflated with air. The air pressure
in the top and the bottom of the tube is the same. Besides
the air pressure, the rim is acted upon by the force of gravi ty
(Fig. 108). Why does the rim not lower? What holds it in a
state of equilibrium?
267. A steam boiler consists of a cylindrical portion and two
hemispherical heads (Fig. 109), all of the same radius. The cylinder
walls are 0.5 em thick. All the parts of the boiler are