Unformatted text preview: 13.6 The position of a point during the interval of time from t=iltoi = ﬁsisgiven by s = —%r3 + ﬁr: + 4: m. [a] 1l‘i'hat is the maximum velocity during this interval oftime.
halal what time does it occur? 11)] What is the acceleration when the velocity is a maximum? 13.]? I-“rugrei-tsivel'}r ties-1:]natures.II it more reaiislie r'i'itidel. lite hin-
engineer nest models the deceleration of the snow petrel by an
equation oi'the l'nrm ti = (III t sin eat). when: C and to are eon-
stnnts. me vitlett measurenrenh [if a bird [ﬂitting nil. he eslimates
that or — l8 and determines that the bird requires 1.42 s to take
off and is moving at (Ll nu‘s when it does. 1ill-'hat is the eonstant ('1’ Problems 13.16f13.1}' l3.44 A. steel ball is released from rest in a eontainer of oil. lts
downward acceleration is a = 2.4 - Lieu ini's‘i. where t! is the
bull‘s veloeitv in ini’s. What is the bull's downward velueitv 2 s
after it is released? Problems 13.44!13.45 13.55 Gas guns are used to investigate the properties of mater-iv
als subjected to high-velocity imparts. A projeelile is aeeeleraleel.
through the barrel of the gun by gas at high pressure. Assume that
the acceleration of the ptoievtile ill “his2 is given by ti = ifs.
where s is the position of the projectile in the barrel in meters and
e is a eonstant that depends on the initial gas pressure behind the
projectile. The projeelile starts from rest at _v = Li m and aeeeler-
ates until it reaches the end nflhe barrel at .r = 3 m. Determine
the value of the eons-taut r necessary for the projectile to leave the
barrel with a velocity ot'2lJt} ma. Problems 13.531156 3.11 When the athlete releases the shot. it is LEE rn above the
pound and its initial velrreit}r is ten = llﬁ "Li's. Determine the
Imimntal distanee the shot travels from the point of release to the
point where it hits the ground. Problem 13.?4 13.85 A projeelile is launehed at lt'lt'l- [Us at till" above the hori-
zontal. The surfaee on whieh it lands is deseribed by the equation
shown. Deten‘nine the I eoordinate ol' the point of impaet. 'ln‘
' I in n _.-'s Problem 13.35 ...
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- Spring '09