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

136 Aptitude Test Problems in Physics

load (and the carriage) is determined by this

horizontal force: ma=mglia 2 — 1. Consequently,

a — 1 = (3/4)g = 7.5 m/s 2.

Fig. 146

On the first segment of the path, the carriage is

accelerated to the velocity v = ati = (3/4) gt i =

30 m/s and covers the distance si in the forward

direction in the straight line:

ail 3

= gt-

a

= 60 m.

2 8 I

Further, it moves at a constant velocity v during

the time interval t 2 = 3 s and traverses the path

of length

ss = vts = 90 m.

Thus, seven seconds after the beginning of motion,
the carriage is at a distance si ss = 150 m in
front of the initial position.
On the third segment, the carriage moves round
a bend to the right. Since the velocity of the car-
riage moving on the rails is always directed along
the carriage, the constant (during the time interval
is = 25.12 s) transverse acceleration a = (3/4) g
is a centripetal acceleration, i.e. the carriage moves
in a circle at a constant velocity v: a = v 2 /R, the
radius of the circle being R = v 2 /a = 120 m. The
path traversed by the carriage in the circle is

as = Rp = vts ,

Si =