Quiz Preparation – UMD Racing e.V.

Quiz „General Engineering“

p2 = p1 * (V1/V2)^gamma
gamma= 1.4

1 / 10

An air as an ideal gas expands adiabatic from a volume of V1 = 1,00l with its pressure of p1 = 10^5 Pa to 1/10 of its original pressure. What volume V2 (in litres) does the gas reach after it’s expansion? Round to two decimal places

2 / 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. 328,1 m^2

b. 314,12 m^2

c. 281,7 m^2

3 / 10

in m, to decimal numbers seperated by a point (example: 150.00), no unit requirment for the solution

4 / 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. 177.06°F

c. 308,.64°F

5 / 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)

6 / 10

A vehicle with the mass 190kg, wheelbase 1,56m and tyre static radius 222mm is weighed. Scales measure 83kg (front) and 107kg (rear) when the car measured on the perfectly flat ground and the same values when the front axle is elevated by 0,85m. What is the car’s COG height? Give answer to the nearest whole number in mm

7 / 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)

8 / 10

A lorry contains an engine with a power of 2.78 J/s. The lorry drives for 36 mins. Calculate the energy transferred in kJ rounded to three decimal places.

9 / 10

During last year acceleration a top speed of 100 km/h was reached. Due to big improvements in the new drivetrain, the new vehicle reaches a top speed of 120 km/h. The aerodynamics chief has some worries about the stability of the rear wing bracing due to the higher aerodynamics load. Given the geometry below, by how much % does the bearing force in point A change in comparison to last year? (The aerodynamic package did not change and therefore some values can be assumed for both vehicles). Give answer rounded to one decimal place.

CL=3.8 CD=1.2 A=1 m² rho=1.1 kg/m³ L1=50 mm L2= 100 mm H1= 125 mm H2= 165mm

10 / 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).

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