For a copper-silver alloy of composition 51 wt% ag-49 wt% cu and at 775˚c (1425˚f) (see animated figure 9.7) do the following: (a) determine the mass fractions of and phases. mass fraction = [the tolerance is +/- 5.0%.] mass fraction = [the tolerance is +/- 5.0%.] (b) determine the mass fractions of primary and eutectic microconstituents. mass fraction primary = [the tolerance is +/- 5.0%.] mass fraction eutectic = [the tolerance is +/- 5.0%.] (c) determine the mass fraction of eutectic . mass fraction eutectic = [the tolerance is +/- 5.0%.]

And, finally, we are asked to compute the mass fraction of eutectic , We.  This quantity is simply the difference between the mass fractions of total  and primary  as

We = W – W' = 0.796 – 0.734 = 0.062

1 a

2 b

3 b

4 d

5 d

6 d

explanation:

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day