Unlock document.
This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
101
*12–96.
It is observed that the skier leaves the ramp Aat an angle
with the horizontal. If he strikes the ground at B,
determine his initial speed and the time of flight .tAB
vA
uA=25°
SOLUTION
4 m
vA
A
3
4
5
uA
102
12–97.
4 m
vA
100 m
A
3
4
5
uA
It is observed that the skier leaves the ramp Aat an angle
with the horizontal. If he strikes the ground at B,
determine his initial speed and the speed at which he
strikes the ground.
vA
uA=25°
SOLUTION
103
12–97. Continued
104
12–98.
SOLUTION
Determine the horizontal velocity of a tennis ball at Aso
that it just clears the net at B. Also, find the distance swhere
the ball strikes the ground.
vA
21 ft
s
7.5 ft
3ft
vA
C
A
B
105
SOLUTION
12–99.
The missile at A takes off from rest and rises vertically to B,
where its fuel runs out in 8 s. If the acceleration varies with
time as shown, determine the missile’s height hB and
speed vB. If by internal controls the missile is then suddenly
pointed 45° as shown, and allowed to travel in free flight,
determine the maximum height attained, hC, and the
range R to where it crashes at D.
R
A
B
D
C
v
B
h
B
45
h
C
106
*12–100.
The projectile is launched with a velocity . Determine the
range R, the maximum height hattained, and the time of
flight. Express the results in terms of the angle and .The
acceleration due to gravity is g.
v0
u
v
0
SOLUTION
y
x
R
h
v0
u
107
SOLUTION
12–101.
The drinking fountain is designed such that the nozzle is
located from the edge of the basin as shown. Determine the
maximum and minimum speed at which water can be
ejected from the nozzle so that it does not splash over the
sides of the basin at B and C.
A
BC
v
A
50 mm
100 mm
250 mm
40
1
00 mm
108
SOLUTION
12–102.
If the dart is thrown with a speed of 10 m
>
s, determine the
shortest possible time before it strikes the target. Also, what
is the corresponding angle
u
A at which it should be thrown,
and what is the velocity of the dart when it strikes the
target?
B
4 m
AvA
u
A
109
12–102. Continued
110
12–103.
If the dart is thrown with a speed of 10 m
>
s, determine the
longest possible time when it strikes the target. Also, what is
the corresponding angle
u
A at which it should be thrown,
and what is the velocity of the dart when it strikes the
target?
B
4 m
AvA
u
A
SOLUTION
111
12–103. Continued
112
*12–104.
The man at Awishes to throw two darts at the target at Bso
that they arrive at the same time. If each dart is thrown with
a speed of determine the angles and at which
they should be thrown and the time between each throw.
Note that the first dart must be thrown at then
the second dart is thrown at uD.
uC17uD2,
uD
uC
10 m>s,
SOLUTION
B
5m
AD
C
u
C
u
D
113
12–105.
The velocity of the water jet discharging from the orifice can
be obtained from ,where is the depth of
the orifice from the free water surface.Determine the time
for a particle of water leaving the orifice to reach point B
and the horizontal distance xwhere it hits the surface.
h=2mv=22gh
SOLUTION
1.5 m
2m A
x
B
vA
114
12–106.
The snowmobile is traveling at 10 m
>
s when it leaves the
embankment at A. Determine the time of fl ight from A to B
and the range R of the trajectory.
SOLUTION
40
3
4
5
B
A
115
12–107.
SOLUTION
The fireman wishes to direct the flow of water from his hose
to the fire at B. Determine two possible angles and at
which
this can be done.Water flows from the hose at
.vA=80 ft>s
u2
u1
20 ft
A
u
B
vA
116
*12–108.
The baseball player Ahits the baseball at and
from the horizontal. When the ball is directly
overhead of player Bhe begins to run under it. Determine
the constant speed at which Bmust run and the distance d
in order to make the catch at the same elevation at which
the ball was hit.
uA=60°
vA=40 ft
>
s
SOLUTION
vA=40 ft/s
A
vA
A
θ
BC
15 ft d
117
12–109.
The catapult is used to launch a ball such that it strikes the
wall of the building at the maximum height of its trajectory.
If it takes 1.5 s to travel from Ato B, determine the velocity
at which it was launched, the angle of release and the
height h.
u,vA
3.5 ft
h
A
B
v
A
u
SOLUTION
Ans:
118
12–110.
An automobile is traveling on a curve having a radius of
800 ft. If the acceleration of the automobile is ,
determine the constant speed at which the automobile is
traveling.
5ft>s2
SOLUTION
119
12–111.
SOLUTION
Determ
i
ne t
h
e max
i
mum constant spee
d
a race car can
have if the acceleration of the car cannot exceed
while rounding a track having a radius of curvature of
200 m.
7.5 m>s2
Ans:
v
=
38.7
m>s
120
SOLUTION
*12–112.
A boat has an initial speed of 16 ft
>
s. If it then increases its
speed along a circular path of radius
r
= 80 ft at the rate of
v
#
= (1.5s) ft
>
s, where s is in feet, determine the time needed
for the boat to travel s = 50 ft.
