# FE Practice Exam 1 Part IV

#### Problem #31

What the standard units used when using the Reynolds Number?

A) ft/s2

B) centipoise

C) kg/s

D) None

#### Problem #32

What is the thermal efficiency for a Carnot engine that operates between 100F and 400K?

A) 75%

B) 77.5%

C) 7.8%

D) 22.3%

#### Problem #33

What is the natural frequency of a body that has a period of oscillation of 2.7 seconds?

A) 2.7 s

B) 0.75 s

C) 2.33 s

D) 4.65 s

#### Problem #34

What cycle is the most efficient?

A) Carnot

B) Brayton

C) Diesel

D) Otto

#### Problem #35

An iron sphere with a mass of 1.5 kg hangs from a 15 cm long spring. If the spring constant is 0.75 N/m what is the period of oscillation when the sphere is pulled down and released?

A) 3.2 s

B) 8.9 s

C) 4.4 s

D) 12.5 s

#### Problem #36

A plane intercepts the coordinate axis at (4,6,10). What are the Miller indices for this plane?

A) (2,3,5)

B) (15,10,6)

C) (-4,-6,-10)

D) (10,6,4)

#### Problem #37

A copper ball that is 1.5 m in diameter has a temperature of 100C. The environment is at 0C. If the emissivity of copper is 0.15 how much power is radiated by the copper ball?

A) 6 w

B) 5,264 W

C) 500 W

D) 1,164 W

#### Problem #38

What would the annuity be over a 20 year period that has an interest rate of 10% and a present worth of $500?

A) $58.75

B) $42.55

C) $8.51

D) $ 63.75

#### Problem #39

A group of dog pulls a sled across a snow covered surface. It takes 5 hours to pull the 200 kg sled 100 kilometers. If the static friction is 0.4 and the dynamic friction is 0.1 what is the average power exerted by the dog sled team?

A) 1,067 W

B) 5,333 W

C) 3,84 kW

D) 266.8 W

#### Problem #40

Reactions on average will proceed faster at a higher temperature because of which of the following?

A) There is less energy in the molecules

B) Molecules collide more frequently

C) The amount of exergy is diminished

D) The energy to start the reaction is higher