Quiz Preparation – UMD Racing e.V.

Quiz „General Engineering“

1 / 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. 314,12 m^2

c. 328,1 m^2

2 / 10

2. A hall with a floor area of 500 m² is to be equipped with underfloor heating, which will be operated at an average temperature of 33°C.

What percentage of the floor area must be used as heating surface in order to ensure an indoor temperature of 18°C when the outside temperature is -15°C?

Result in m^2 as an integer

3 / 10

3. Calculate the maximum possible cornering speed (in kph) for the following FSAE car when going through a 20 m radius corner.

m = 260kg; cl *A * Rho = -6 kg/m; Tyre coefficient of friction = 1.5; g = 9.81 m/s^2.

The vehicle can be treated as a point mass, driving resistances neglected. Round to 1 decimal

4 / 10

4. Calculate the gravitational potential energy of a 4 kg object at 15 m above Earth’s surface with gravitational field strength of 9.81 N/kg. Give answer to three significant figures in J.

5 / 10

5. A ball at a height of 20ft on Earth with a gravitational field strength of 9.81 N/kg, gained 284 J of gravitational potential energy. Calculate the mass of the ball. Give answer to two decimal place in kg.

6 / 10

What temperature would occur at the stagnation point of an aircraft flying at a speed of

V_{1} = 2000 km/h

, assuming that the air behaves as an ideal gas under these conditions? The temperature of the undisturbed air is theta_1 = -30°C.

a. 254.53°F

b. 308,.64°F

c. 177.06°F

7 / 10

7. In a gas pipe, the gas pressure pG is measured using a U-tube manometer connected at the bottom. Above the meniscus of the measuring liquid (mercury with density ρQ) on the gas side, there is a column of water with height h₂ and density ρW.
Question:
What negative pressure △pU (vacuum) exists in the pipe compared to the external pressure p₀?

Result in Pa, two decimal numbers seperated by a point (exp. 15.3). Do not put the Unit in the field below.

8 / 10

A metal piece heated to

θ_1,M=1000∘C

with a mass of

M_M=6.5 kg

was cooled in a completely heat-insulated iron container filled with water. The mass of the water in the container is

M_W=10 kg

and the mass of the container is

M_B=2 kg.

The initial temperatures of the water and the container were the same and amounted to

θ_1,W=10∘C

. After complete thermal equilibrium between the immersed metal piece, the water, and the container, a temperature of

was established.
What is the average specific heat capacity of the metal piece

c

in the temperature range between

and

Input the result in kJ/(kg*K), round to 3 decimal numbers sperated by a point (example: 0.136).

9 / 10

9. The given gearbox consists of two gear sets with wheels 1, 2 and 3, 4 respectively. The wheels are fixed to their shafts. Calculate the drive speed (in rpm) of wheel 4?

Given: n1=600 rpm, z1=18, z2=90, z3=24, z4=120

10 / 10

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 = 300 km/h, μF = 0.15, g = 9.81 m/s2.
Give your answer in meters, rounded to four significant places.

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