Quiz Preparation – UMD Racing e.V.

Quiz „General Engineering“

1 / 10

If the density of aluminium is 2.71 kg/m^3, find the volume of a 0.888 kg of aluminium. Give answer in m^3 with two decimal places.

2 / 10

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.

3 / 10

A helicopter of mass 4200 kg is carrying a crate using a light extensible rope. The crate has a total mass of 800 kg, including its contents. The helicopter and crate are accelerating upwards at 2.0 ms^-2. What is the tension in the rope? Use gravititational field strength g is 9,81 N/kg. Air resistance can be ignored. Give answer to nearest whole number in Newtons

4 / 10

A 30 lbs model helicopter flying at 51 mph, calculate its kinetic energy. Answer in J to 3 significant figures.

5 / 10

in cm^3, round to decimal numbers sperated by point (13.5) no unit int the answer

6 / 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. 4 mins

b. 0 mins

c. 2 mins

7 / 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.

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

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. 281,7 m^2

c. 314,12 m^2

10 / 10

Before the endurance you pump nitorgen in your tires at a temperature of 20°C and 0.7 bar relative pressure. Knowing, that during the endurance the maximal tyre temperature will be around 60°C, what will be the maximal relative pressure of the tyre? Give answer in bar to two decimal places.

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