Dynamics 2e 767
of McGraw-Hill, and must be surrendered upon request of McGraw-Hill. Any duplication or distribution, either in print or electronic form, without the
permission of McGraw-Hill, is prohibited.
768 Solutions Manual
Problem 4.76
Crates
A
and
B
of mass
50 kg
and
75 kg
, respectively, are released from rest.
The linear elastic spring has stiffness
kD500 N=m
. Neglect the mass of the
pulleys and cables and neglect friction in the pulley bearings.
If
kD0:25
and the spring is initially unstretched, determine the speed of
Bafter Aslides 4m.
Solution
Dynamics 2e 769
of McGraw-Hill, and must be surrendered upon request of McGraw-Hill. Any duplication or distribution, either in print or electronic form, without the
permission of McGraw-Hill, is prohibited.
770 Solutions Manual
Problem 4.77
Crates
A
and
B
of mass
50 kg
and
75 kg
, respectively, are released from rest.
The linear elastic spring has stiffness
kD500 N=m
. Neglect the mass of the
pulleys and cables and neglect friction in the pulley bearings.
If
kD0:25
and the spring is initially stretched
1
m, how far does
A
slide
before the system momentarily comes to rest?
Solution
of McGraw-Hill, and must be surrendered upon request of McGraw-Hill. Any duplication or distribution, either in print or electronic form, without the
permission of McGraw-Hill, is prohibited.
Dynamics 2e 771
of McGraw-Hill, and must be surrendered upon request of McGraw-Hill. Any duplication or distribution, either in print or electronic form, without the
permission of McGraw-Hill, is prohibited.
772 Solutions Manual
Problem 4.78
The crates
A
and
B
of weight
WAD50 lb
and
WBD75 lb
, respectively, are
connected by a pulley system. The system is released from rest and friction
between
A
and the horizontal surface is insufficient to prevent slipping. The
cables in the pulley system are inextensible, and the coefficient of kinetic
friction between the crate Aand the horizontal surface is k.
If kD0, determine the speed of Bafter Aslides 10 ft.
Solution
We model
A
and
B
as a system of particles subject to the weights of
A
and
B
,
mAg
and
mBg
, respectively, the reaction with the ground
of McGraw-Hill, and must be surrendered upon request of McGraw-Hill. Any duplication or distribution, either in print or electronic form, without the
permission of McGraw-Hill, is prohibited.
774 Solutions Manual
Problem 4.79
The crates
A
and
B
of weight
WAD50 lb
and
WBD75 lb
, respectively, are
connected by a pulley system. The system is released from rest and friction
between
A
and the horizontal surface is insufficient to prevent slipping. The
cables in the pulley system are inextensible, and the coefficient of kinetic
friction between the crate Aand the horizontal surface is k.
Determine the required value of
k
so that the speed of
B
is
27 ft=s
after it
drops 15 ft.
Solution
We model
A
and
B
as a system of particles subject to the weights of
A
and
B
,
mAg
and
mBg
, respectively, the reaction with the ground
Dynamics 2e 775
of McGraw-Hill, and must be surrendered upon request of McGraw-Hill. Any duplication or distribution, either in print or electronic form, without the
permission of McGraw-Hill, is prohibited.
776 Solutions Manual
Problem 4.80
The crates
A
and
B
of weight
WAD50 lb
and
WBD75 lb
, respectively, are
connected by a pulley system. The system is released from rest and friction
between
A
and the horizontal surface is insufficient to prevent slipping. The
cables in the pulley system are inextensible, and the coefficient of kinetic
friction between the crate Aand the horizontal surface is k.
If kD0:25, determine the speed of Aafter Bdrops 15 ft.
Solution
of McGraw-Hill, and must be surrendered upon request of McGraw-Hill. Any duplication or distribution, either in print or electronic form, without the
permission of McGraw-Hill, is prohibited.