Quiz Preparation – UMD Racing e.V.

Quiz „General Engineering“

1 / 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

2 / 10

An object is fired vertically upwards from the ground at time t = 0 s in still air at a speed of 9.6 m/s. On the way up, what is the height of the object above the ground when it has a speed of 1.9 m/s. At what time does it reach this height on the way down? Give both answers separated by a comma to one decimal place.

3 / 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).

4 / 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)

5 / 10

An object is fired vertically upwards from the ground at time t = 0 s in still air at a speed of 8.0 m/s. On the way up, what is the height of the object above the ground when it has a speed of 2.0 m/s. At what time does it reach this height on the way down? Give both answers separated by a comma to one decimal place.

6 / 10

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

7 / 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

8 / 10

How high (in m) can a column of liquid be lifted by a reciprocating piston, neglecting leakage and losses, if the air pressure is 101300 Pa and the pressure p₁ approaches zero?

Example Input 14.3 (use a point, no unit)

9 / 10

Calculate the force Fc working at point C. Give answer in kN rounded to one decimal place.

Forces at point A: Rax = 3kN, Ray = 9kN, Ma = 10kN/m

10 / 10

For a horizontally positioned, non-insulated steam pipe with a length of l=3 m and a diameter of d_a=0.1 the convective heat loss Q_point is to be calculated. The temperature of the surrounding air is θ_f=30∘C and that of the outer wall surface is θ_w=170∘C.

Input the result in kW and round to two decimal numbers seperated by a point without thr unit (example: 145.35)

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