Chapter 1 - Section A - Mathcad Solutions
1.4 The equation that relates deg F to deg C is: t(F) = 1.8 t(C) + 32. Solve this equation by setting t(F) = t(C). Guess solution:

t

0

Given

t = 1.8t

32

Find ( t)

40

Ans.

1.5 By definition:

P=

F A

F = mass g

Note: Pressures are in gauge pressure.

P

3000bar

D

4mm

A

4

D

2

A

12.566 mm

2

F

PA

g

9.807

m s
2

mass

F g

mass

384.4 kg

Ans.

1.6 By definition:
P 3000atm

P=
D

F A
0.17in

F = mass g
A

4

D

2

A

0.023 in

2

F

PA

g

32.174

ft sec
2

mass

F g

mass

1000.7 lbm

Ans.

1.7 Pabs =

gh

Patm

13.535

gm cm
3

g

9.832

m s
2 …ver más…

The obvious advantage of coal is that it is cheap if it is used as a heat source. Otherwise it is messy to handle and bulky for tranport and storage. Gasoline is an important transportation fuel. It is more convenient to transport and store than coal. It can be used to generate electricity by burning it but the efficiency is limited. However, fuel cells are currently being developed which will allow for the conversion of gasoline to electricity by chemical means, a more efficient process. Electricity has the most uses though it is expensive. It is easy to transport but expensive to store. As a transportation fuel it is clean but batteries to store it on-board have limited capacity and are heavy.

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1.24 Use the Matcad genfit function to fit the data to Antoine's equation. The genfit function requires the first derivatives of the function with respect to the parameters being fitted.
A

Function being fit:

f ( T A B C)

e

B T C

First derivative of the function with respect to parameter A

d dA

f ( T A B C)

exp A

B T C

First derivative of the function with respect to parameter B

d dB

f ( T A B C)

1 T C

exp A

B T C

First derivative of the function with respect to parameter C

d f ( T A B C) dC
18.5 9.5 0.2 11.8 t 23.1 32.7 44.4 52.1 63.3 75.5

B (T C)
2

exp A

B T C

3.18 5.48 9.45 16.9 Psat 28.2 41.9 66.6 89.5 129 187

6

T

t

273.15