SOLUTIONS MANUAL
All Chapters Included
, Chapter 1
Exercise 1.1 Lucy is one of the earliest hominids (Australopithecus afarensis) who roamed
Ethiopia between five and four million years ago. She was bipedal and her height was only
1 m. By using geometrical estimates, calculate her weight. Johanna, Lucy’s modern
counterpart, is 1.70 m high and weighs 70 kg. From Fig. E1.1, estimate her femur bone
diameter. How does it compare with the diameter of a modern human?
Solution:
Lucy’s weight: 70kg/1.7m*1m=41.17kg
Compared to her height in Fig. E1.1, her femur bone diameter is 2-3cm.
Modern people has a femur bone of about 1.5-2inch (5cm), so Lucy’s femur bone is smaller
than modern human.
Exercise 1.2 The early chopper shown in Fig. 1.1 has a diameter of approximately 10 cm.
(a) Determine its weight, knowing that it is made of basalt (obtain the density from the
web).
(b) Estimate the velocity it can reach, thrust by the energetic arms of Lucy (see Fig. E1.1).
(c) What force can it generate if it is decelerated to zero over a distance equal to the skull
thickness of Luciano, Lucy’s suitor?
(d) Assuming that bone has a flexure strength equal to 120 MPa, establish whether the
blow force is sufficient to crack Luciano’s skull.
Solution:
(a) The density of basalt is 2.8-3.0g/cm3, D=10cm, M=ρ*V=1.52kg.
(b) Lucy’s arm is about 20cm long. The distance of chopper travels in her hand is about 50
cm. if she can throw the chopper in 0.2s, it can reach to the velocity of 2.5 m/s.
1
(c) ��2 = � ∗ �, l is estimated as 2cm. so F= 237.5N.
2
(d) = / , the area of contact is estimated as 0.01 cm2, therefore P= 237.5 MPa. It is
sufficient to crack Luciano’s skull.
Exercise 1.3 Why are gold, copper, and silver three of the few metals that are found native
(in metallic form)?
Solution:
Over geological time scales, very few metals can resist natural weathering processes like
oxidation, which is why generally only the less reactive metals (Au, Cu and Ag) are found
as native metals.
Exercise 1.4 The Fe–Ni alloy is also found in native form, and some important religious
and archaeological monuments use this alloy. What is the source of this material?
All Chapters Included
, Chapter 1
Exercise 1.1 Lucy is one of the earliest hominids (Australopithecus afarensis) who roamed
Ethiopia between five and four million years ago. She was bipedal and her height was only
1 m. By using geometrical estimates, calculate her weight. Johanna, Lucy’s modern
counterpart, is 1.70 m high and weighs 70 kg. From Fig. E1.1, estimate her femur bone
diameter. How does it compare with the diameter of a modern human?
Solution:
Lucy’s weight: 70kg/1.7m*1m=41.17kg
Compared to her height in Fig. E1.1, her femur bone diameter is 2-3cm.
Modern people has a femur bone of about 1.5-2inch (5cm), so Lucy’s femur bone is smaller
than modern human.
Exercise 1.2 The early chopper shown in Fig. 1.1 has a diameter of approximately 10 cm.
(a) Determine its weight, knowing that it is made of basalt (obtain the density from the
web).
(b) Estimate the velocity it can reach, thrust by the energetic arms of Lucy (see Fig. E1.1).
(c) What force can it generate if it is decelerated to zero over a distance equal to the skull
thickness of Luciano, Lucy’s suitor?
(d) Assuming that bone has a flexure strength equal to 120 MPa, establish whether the
blow force is sufficient to crack Luciano’s skull.
Solution:
(a) The density of basalt is 2.8-3.0g/cm3, D=10cm, M=ρ*V=1.52kg.
(b) Lucy’s arm is about 20cm long. The distance of chopper travels in her hand is about 50
cm. if she can throw the chopper in 0.2s, it can reach to the velocity of 2.5 m/s.
1
(c) ��2 = � ∗ �, l is estimated as 2cm. so F= 237.5N.
2
(d) = / , the area of contact is estimated as 0.01 cm2, therefore P= 237.5 MPa. It is
sufficient to crack Luciano’s skull.
Exercise 1.3 Why are gold, copper, and silver three of the few metals that are found native
(in metallic form)?
Solution:
Over geological time scales, very few metals can resist natural weathering processes like
oxidation, which is why generally only the less reactive metals (Au, Cu and Ag) are found
as native metals.
Exercise 1.4 The Fe–Ni alloy is also found in native form, and some important religious
and archaeological monuments use this alloy. What is the source of this material?
