Quiz Preparation – UMD Racing e.V.

Quiz „General Engineering“

1 / 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)

2 / 10

A water tank under a pressure of p = 117.72 kPa has three pipes connected to it, which are sealed 5 meters below the water surface by three plates with areas A₁, A₂, and A₃.
Task:
Sort the pressures p₁, p₂, and p₃ according to their magnitude.

a. p1=p2=p3

b. p2>p1>p3

c. p2=p1>p3

d. p2>p3>p1

e. p1>p2>p3

3 / 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)

4 / 10

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.

5 / 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)

6 / 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.

7 / 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.

8 / 10

The kinetic energy of a 8 lbs 4 oz box as it was dropped reaching ground is 10125J. Determine the speed as it lands. Give answer to one decimal place in m/s.

9 / 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.

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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