\fdO'^ - Old Forge Coal Mines

ELEMENTARY MECHANICS.
(355)
(QUESTIONS 355-453.)
Use formulas 18 and 8.
Time it would take the ball to fall to the ground = t —
— = 4/ -———- = .
g
32.16
58484 sec.
The space passed through by a body having a velocity of
500 ft. per sec. in .58484 of a second = 5 = F/ = 500 X
.58484 = 292.42 ft. Ans.
(356)
Use formula 7.
\% X 3.1416 X 160 „_ __ . .
— — — 55. 85 ft. per sec. Ans.
(357) 160 H- 60 X 7 = %r revolution in \ sec. 360° X
A = 137L = 137° 8'
34^
. Ans.
(358) {a) See Fig. 20. 36' = 3'. 4 -^ 3 = | = number
o
of revolutions of pulley to one revolution of fly-wheel.
4
54 X o
= 72 revolutions of pulley and drum per min. 100 -r-
— X 3. 1416 = 21.22 revolutions of drum to raise elevator
I
J
21 22
100 ft. —-^ X 60 = 17.68 sec. to travel 100 ft. Ans.
(^) 21.22 : -r :: 30 : 60, ox x = ^
^^ = 42.44 rev.