Water expands significantly when it freezes: a volume increase at about 9% occurs. As a result of this expansion and because of the formation and growth of crystals as water freezes anywhere from 10% to 30% of biological cells are burst when animal or plant material is frozen. Discuss the implications of this cell damage for the prospect of preserving human bodies by freezing so that they can he thawed at some future date when it is hoped that all diseases are curable.
Water expands significantly when it freezes: a volume increase at about 9% occurs. As a result of this expansion and because of the formation and growth of crystals as water freezes anywhere from 10% to 30% of biological cells are burst when animal or plant material is frozen. Discuss the implications of this cell damage for the prospect of preserving human bodies by freezing so that they can he thawed at some future date when it is hoped that all diseases are curable.
Water expands significantly when it freezes: a volume increase at about 9% occurs. As a result of this expansion and because of the formation and growth of crystals as water freezes anywhere from 10% to 30% of biological cells are burst when animal or plant material is frozen. Discuss the implications of this cell damage for the prospect of preserving human bodies by freezing so that they can he thawed at some future date when it is hoped that all diseases are curable.
Truck suspensions often have "helper springs" that engage at high loads. One such arrangement is a leaf spring with a helper coil spring mounted on the axle, as in the figure below. The helper spring engages when the main leaf spring is compressed by distance yo, and then helps to
support any additional load. Consider a leaf spring constant of 5.45 × 105 N/m, helper spring constant of 3.60 × 105 N/m, and y = 0.500 m.
Truck body
Dyo
Axle
(a) What is the compression of the leaf spring for a load of 4.90 × 105 N?
m
(b) How much work is done compressing the springs?
]
A skier of mass 75 kg is pulled up a slope by a motor-driven cable.
(a) How much work is required to pull him 50 m up a 30° slope (assumed frictionless) at a constant speed of 2.8 m/s?
KJ
(b) What power (expressed in hp) must a motor have to perform this task?
hp
A block of mass 1.4 kg is attached to a horizontal spring that has a force constant 900 N/m as shown in the figure below. The spring is compressed 2.0 cm and is then released from rest.
a
x = 0
x
b
(a) A constant friction force of 4.4 N retards the block's motion from the moment it is released. Using an energy approach, find the position x of the block at which its speed is a maximum.
cm
(b) Explore the effect of an increased friction force of 13.0 N. At what position of the block does its maximum speed occur in this situation?
cm
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