Quiz Preparation – UMD Racing e.V.

Quiz „General Engineering“

1 / 10

Three inductors are connected as shown in the following figure:

Given that L1 = 2L2, find L1 and L2 such that the equivalence inductance is L = 0.7 H.
Give your answers in Henry, rounded to three decimal places separated by a comma (L1, L2)

2 / 10

In a cylinder, air is compressed isothermally at ambient temperature (

θ_U=20∘C)

p_{1} = 0.1 MPa

p_{2} = 0.5 MPa

Calculate the change in the specific entropy of the air in the cylinder.

Round to two decimal numbers sperated by a point. Input in J/(kgK). (Example -365.26)

3 / 10

Calculate the cornering speed during Skidpad (you can use the centerline radius in the rules) using following information:

μ_y = 1.4, m = 240 kg, c_L = 3.2, A = 1 m^2, ρ = 1.1 kg/m^3

It is assumed, that there is no weight transfer and all 4 tires are at the optimal grip level. Answer in m/s rounded to one decimal place.

4 / 10

A cat of mass 12 kgs ran at 65mph. What is its kinetic energy? Answer in J to the nearest whole number

5 / 10

A spring in a church clock has a spring constant of 10 N/m. What is its elastic potential energy store if it is stretched 8 m? Give answer in Joules to three significant figures.

6 / 10

A racing car rolls to a stop on a horizontal course with an initial speed of v. It decelerates
only by friction with a rolling resistance of μF, which is supposed to be independent of
the current velocity.
What is the distance s the car needs to stop?
v = 230mph, μF = 0.17, g = 9.81 m/s2.
Give your answer in meters, rounded to four significant places.

7 / 10

Answer in MJ, round to one decimal number (example 45.7), no unit in the answer

8 / 10

You would like to drink a cup of very hot coffee with milk early in the morning, but you
are in a hurry and have only 5 minutes until you have to leave for work. At which time
after brewing should you add the cold milk to the coffee and stir in order to decrease the
temperature of the mixture as much as possible:
a) 0 minutes (immediately),
b) 2 minutes, or
c) 4 minutes?
Suppose that the stirring can be done instantaneously and that you need the last one
minute for drinking.

brew temperature C = 80 ◦C, temperature of milk = M = 10 ◦C, room temperature
0 = 20 ◦C, volume of coffee VC = 300 ml, volume of milk VM = 100 ml, specific heat
capacity of coffee cC = 4180 J/(kgK), specific heat capacity of milk cM = 3500 J/(kgK).

Please enter only the letter of the corresponding answer

a. 0 mins

b. 4 mins

c. 2 mins

9 / 10

An air stream

dot{M}_L = 5.5 kg/s,

cp_L=1 kJ/(kgK)

is to be heated in a plate heat exchanger from

θ_L′=20∘C

θ_L′′=150∘C

. For this purpose, a flue gas stream

dot{M}_R = 7.22

cp_R=1.1 kJ/(kgK)

with a temperature of

θ_R′=300∘C

is available. The overall heat transfer coefficient is

W/(m^2*K)

.
What is the required heating surface AAA if the fluid streams are arranged in counterflow?

a. 281,7 m^2

b. 328,1 m^2

c. 314,12 m^2

10 / 10

The previous season you could recuperate only 25% of your initially stored energy, but this season a big improvement in your drivetrain allows you to recuperate 63% of the initially stored energy. Knowing that you had 9.6 kWh of energy in your accumulator during the last season, how much energy must your new accumulator have, if you assume, that it’s the same length and speed? Give answer in kWh to one decimal place.

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