PROBLEM 11.45
Two rockets are launched at a fireworks display. Rocket A is launched
with an initial velocity
0
v
100 m/s and rocket B is launched t
1
seconds
later with the same initial velocity. The two rockets are timed to explode
simultaneously at a height of 300 m as A is falling and B is rising.
Assuming a constant acceleration g 9.81
2
m/s
, determine (a) the time t
1
,
(b) the velocity of B relative to A at the time of the explosion.
PROBLEM 11.46
Car A is parked along the northbound lane of a highway, and car B is traveling in the southbound lane at a
constant speed of 60 mi/h. At
0,t
A starts and accelerates at a constant rate
,
A
a
while at
5s,t
B begins to
slow down with a constant deceleration of magnitude
/6.
A
a
Knowing that when the cars pass each other
294 ftx
and
,
A
B
vv
determine (a) the acceleration
,
A
a
(b) when the vehicles pass each other, (c) the
distance d between the vehicles at
0.t
PROBLEM 11.46 (Continued)
PROBLEM 11.47
The elevator shown in the figure moves downward with a constant velocity of
4 m/s. Determine (a) the velocity of the cable C, (b) the velocity of the
counterweight W, (c) the relative velocity of the cable C with respect to the
elevator, (d) the relative velocity of the counterweight W with respect to the
elevator.
PROBLEM 11.48
The elevator shown starts from rest and moves upward with a constant
acceleration. If the counterweight W moves through 30 ft in 5 s, determine
(a) the acceleration of the elevator and the cable C, (b) the velocity of the
elevator after 5 s.
Problem 11.49
An athlete pulls handle A to the left with a
constant velocity of 0.5 m/s. Determine (a)
the velocity of the weight B, (b) the
relative velocity of weight B with respect
to the handle A.
Problem 11.50
An athlete pulls handle A to the left with a constant
acceleration. Knowing that after the weight B has been
lifted 4 in. its velocity is 2 ft/s, determine (a) the
accelerations of handle A and weight B (b) the velocity and
change in position of handle A after 0.5 sec.
PROBLEM 11.51
Slider block B moves to the right
with a constant velocity of 300
mm/s. Determine (a) the velocity
of slider block A, (b) the velocity
of portion C of the cable, (c) the
velocity of portion D of the cable,
(d) the relative velocity of portion
C of the cable with respect to slider
block A.
PROBLEM 11.51 (Continued)
PROBLEM 11.52
At the instant shown, slider block
B is moving with a constant
acceleration, and its speed is 150
mm/s. Knowing that after slider
block A has moved 240 mm to the
right its velocity is 60 mm/s,
determine (a) the accelerations of
A and B, (b) the acceleration of
portion D of the cable, (c) the
velocity and change in position of
slider block B after 4 s.