Chapter 12: Solids Flashcards
Muller’s micrograph, shown in the chapter-opener photo reveals
the positions of atoms.
The crystals that make up minerals are composed of
atoms with a definite geometrical arrangement.
The crystals that make up minerals are composed of
atoms with a definite geometrical arrangement.
Atoms in a crystal are held together by
electrical bonding forces.
Which of these has the greatest density: 10 kg of concrete, 2 kg of concrete, 3 kg of iron or 1 g of lead?
1 g of lead
When a given mass of water freezes, it undergoes a
decrease in density.
An elastic material is one in which
original shape is restored when a deforming force is removed.
According to Hooke’s law, if you hang by a tree branch and note how much it bends, then hanging with twice the weight normally produces
twice the bend.
F ~ ∆x; so twice the F means twice the ∆x.
A pair of vertical springs, side-by-side, equally support a 20-N load. If the load is doubled and the elastic limit of the springs is not reached, then the tension in each spring will be
20 N. Tension in each spring supporting the 20 N load will be 10 N. Doubling the load doubles each tension to 20 N.
When you sit in the middle of a horizontal bench supported at its ends, the top side of the bench is
compressed and the bottom is stretched.
The shape that has the greatest strength in construction is the
triangle.
Opposite flanges in a properly positioned horizontal I-beam supported at each end undergo
compression in the top and tension in the bottom flange.
Most of the stone arches built by people in ancient times took the shape of a
semicircle
The catenary idea was central in the design of the
Gateway Arch in St. Louis.
Which of these has more combined surface area: 1 kg of grapes, 1 kg of raisins, 1 kg of potatoes, 1 kg of squash?
1 kg of raisins
Suppose you scale up a model machine by a factor of 3. Then its volume is
27 times as much and its surface area is 9 times as much.
Remember the rule: When something is scaled upward, area increases as the square of the increase (3^2 in this case) and volume as the cube of the increase (3^3).
When you scale up an object to four times its linear size, the surface area increases by
16 and the volume by 64. When something is scaled upward by 4, area increases as the square of the increase, 4^2 = 16, and volume by the cube, 4^3 = 64.
Four small spheres of mercury coalesce to form a single sphere. Compared with the combined surface area of the smaller spheres, the surface of the big sphere is
less.
If Alice in Wonderland shrinks to one-tenth her size, the ratio of her surface area/volume will
increase. Although both her surface area and volume decrease, there is great decreases in the volume, hence the ratio surface area/volume increases.
The effects of scaling are beneficial to small creatures: a) that get wet; b) that fall from great heights; c) who are hungry; d) all of the above.
b) that fall from great heights.
The linking together of atoms to form larger structures, including solids.
Atomic bonding
The mass of a substance per unit volume.
Density
density = mass / volume
Weight density is weight per unit volume:
Weight density = weight / volume
The amount of stretch or compression of an elastic material is directly proportional to the applied force.
Hooke’s law
The study of how size affects the relationships among weight, strength, and surface.
Scaling
