Quiz Preparation – UMD Racing e.V.

Quiz „General Engineering“

1 / 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

2 / 10

Frage

a. Yes

b. Nein

c. Depends on y

3 / 10

Calculate the pull force on the plate in Newton. Round to 2 numbers seperated by a point (exanple: 9.13)

4 / 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

5 / 10

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

6 / 10

Calculate the force Fc working at point C.

Rax = 4kN, Ray = 10 kN

Rbx =5 kN, Rby = 8 kN

7 / 10

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.

8 / 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

9 / 10

Calculate the cornering speed during Skidpad (you can use the centerline radius in the rules) using following information:

μ_y = 1.4, m = 240 kg, c_L = 3.2, A = 1 m^2, ρ = 1.1 kg/m^3

It is assumed, that there is no weight transfer and all 4 tires are at the optimal grip level. Answer in m/s rounded to one decimal place.

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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