Aptitude Test Problems in Physics Science for Everyone by S Krotov ( PDFDrive.com )

Solutions

175

motion in a straight line. At a certain instant, the

left load is acted upon along the vertical by a force

mg T, and the right load by a force mg —

T cos (p (Fig. 176, the vertical axis is directed

downwards). Here 2' is the tension of the thread.

Fig. 176 Fig. 177

Hence it follows that the difference in the vertical
components of the accelerations of the right (a 1 )
and left (a 2 ) loads, given by
7 '
al — a 2 = g— — OS (I) ) g— )

T

— (1—cos (p),

is always nonnegative. Since at the initial moment
the relative distance and the relative vertical veloc-
ity of the loads are equal to zero, the difference
in the ordinates of the right and left loads will
increase with time, i.e. at any instant the right
load is lower than the left one.
1.75. Let the right and left threads be deflected
respectively through angles and a from the ver-
tical (Fig. 177). For the rod to remain in the ver-
tical position, the following condition must be
satisfied:

T 1 sin a = T 2 sin (3, (1)